Do other graphics-intensive programs cause the PC to shut down? Games etc? This is an old program but gives the graphics hardware some work to do; click here
Leave it running full screen for a while, if it works at all.If it crashes the machine, go to the manufacturer's site and download VGA/graphics drivers, make sure DirectX is up to date; click here
Check current DirectX version by going to start menu/run, type
Still worth reinstalling even if it appears up to date, files may be missing.