Delphi problem...

procedure ScreenShot (Image : TBitmap);
var
DC : HDC;
begin
DC := GetDC (GetDesktopWindow);
try
Image.Width := GetDeviceCaps (DC, HORZRES);
Image.Height := GetDeviceCaps (DC, VERTRES);
BitBlt(Image.Canvas.Handle, 0, 0, Image.Width,
Image.Height,DC, 0, 0, SRCCOPY);
finally
ReleaseDC (GetDesktopWindow, DC);
end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
ScreenShot(Image1.Picture.Bitmap);
end;