VOID clearDisplay( HWND hwnd )
{
RECT rc;
HDC hdc;
GetWindowRect( hwnd, &rc );
if( rc.top >0 )
{ rc.top=0; }
hdc = GetDC( hwnd );
FillRect( hdc , &rc , (HBRUSH) GetStockObject(WHITE_BRUSH) );
ReleaseDC(hwnd, hdc);
}/* end function */