#define SM_CXSCREEN 0           && Screen Width 
#define SM_CYSCREEN 1           && Screen Height  
#define SM_CXFULLSCREEN 16 && Widht (Client area)
#define SM_CYFULLSCREEN 17 && Height (Client area)

DECLARE INTEGER GetSystemMetrics IN Win32API;
INTEGER nIndex

? GetSystemMetrics(SM_CXSCREEN)
? GetSystemMetrics(SM_CYSCREEN)
? GetSystemMetrics(SM_CXFULLSCREEN)
? GetSystemMetrics(SM_CYFULLSCREEN)