char regname[] = "SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run";
HKEY hkResult;
int ret;
ret = RegOpenKeyEx(HKEY_LOCAL_MACHINE, regname, 0, KEY_ALL_ACCESS, &hkResult); //打开关键字
ret = RegSetValueEx(hkResult, "door", 0, REG_EXPAND_SZ, (unsigned char *)"%systemroot%\\door.exe", 25); //设置键值
应该是权限问题,我记得是需要在项目设置里设置成需要admin权限的