read boot sector using C on windows8

i tried to read the boot sector using this program

int lire_secteur(int num_sect,unsigned char* buf)
{
int retCode = 0;
unsigned char secteur[512];
char disque[10]   ;
char partition ;
FILE* device ;
do
{
    disque[0]='\0'  ;       
    scanf("%c",&partition) ;
    if (partition=='0')
    {
        strcpy(disque,"\\\\.\\PHYSICALDRIVE0") ;
    }
    else
    {
        sprintf(disque,"\\\\.\\%c:",partition) ;
    }
    device = fopen(disque, "rb+");
}

while (device == NULL) ;
fseek( device,num_sect*512 , SEEK_SET );
if (fread (secteur, 512,1, device) < 1)
{
    printf("erreur\n");
    return 1 ;
}
else
{
    memcpy(buf,secteur, 512);
    retCode=0;
}
return retCode;
}

i have successfully read all sectors in the hard drive but when i want to read the boot sector i have this:

is the problem in my code or it'is due to windows8 ?