Hey guys! I dont know whats problem but my friend give me some source codes for turn on and turn off monitor:

turn off:
SendMessage(HWND_BROADCAST, WM_SYSCOMMAND, SC_MONITORPOWER, (LPARAM) 2);

turn on:
SendMessage(HWND_BROADCAST, WM_SYSCOMMAND, SC_MONITORPOWER, (LPARAM) -1);

So it show me like 6 errors .. so can someone help me ?? and i need another 1 so someone know for to change a administrator password on computer ?