ALT key is not functioning

[cva]

Hi everyone,

Im having problem with the ALT key as it does't functions when pressed. The other keys are OK.Can u guys give me some suggestion what minght be the problem...TQ.

Code:
void OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags)
{
BOOL vkControl = (GetKeyState( VK_CONTROL ) < 0);
BOOL vkAlt = (GetKeyState( VK_MENU ) < 0);
}

This code i used to check whether the keys function...Control is OK except for MENU(ALT).