   Why GetDC(NULL) is not recommended in WinVista anymore?
  In PDC2005 presentation "Direct 3D Part 1:  Utilizing The Maximum Power Of The GPU In Your Graphic-Intensive Windows Vista ("Longhorn") Application" Rudolph Balaz wrote: "Actions may disable Desktop CompositionGetDC(NULL), Locking GDI primary surface"(In other words, it may damages Aero Glass interface!)So is there another way to correctly get a copy of the screen in GDI, or in Direct3D mode?[Edited by - Malder1 on December 14, 2005 3:17:04 PM]
  I think there is now an explicit api to do this, unfortunetly I can't remember it.  Since Aero Glass uses the gpu locking the buffer with a ::GetDC(NULL) call requires it to copy the composited video card buffer to be transfered back into agp memory, which stalls both the cpu and video card.  If you just want a screen cap you should be fine, but you wouldn't want to create a movie this way:)CheersChris   