procedure SetNumLock(bState:Boolean);
var

KeyState : TKeyboardState;
begin

GetKeyboardState(KeyState);
if ( (bState) and (not ((KeyState[VK_NUMLOCK] and  1 )= 1 ) ) or
( (not (bState)) and ((KeyState[VK_NUMLOCK] and  1 )= 1 ))) then
// Simulate a key press
keybd_event(VK_NUMLOCK, $ 45 , (KEYEVENTF_EXTENDEDKEY or  0 ),  0 );
// Simulate a key release
keybd_event( VK_NUMLOCK, $ 45 ,  (KEYEVENTF_EXTENDEDKEY or
KEYEVENTF_KEYUP),  0 );
end;