얘길 하시지...^^
예제를 보냅니다.

/**********************************************************************/
    HDC dc;
    RECT r;
    GetWindowRect(GetForegroundWindow(),&r);
    dc = GetWindowDC(GetForegroundWindow());
    Graphics::TCanvas *MyCanvas = new Graphics::TCanvas;
    MyCanvas->Handle = dc;
    Image1->Width = r.right - r.left;
    Image1->Height = r.bottom - r.top;
    Image1->Picture->Bitmap->Width = r.right - r.left;
    Image1->Picture->Bitmap->Height = r.bottom - r.top;
    Image1->Picture->Bitmap->Canvas->CopyRect(
                  Rect(0,0,Image1->Width,Image1->Height),MyCanvas,
                  Rect(0,0,Image1->Width,Image1->Height));
    delete MyCanvas;
    ReleaseDC(NULL,dc);
/***********************************************************************/

주위: 이 예제대로 하면 현재 활성화되어있는 창이 화면에 나옵니다.
      응용하여 사용하십시오.