direct3D issue I can't solve 'till now

Games Program like Diablo 2 and other applications
requiring direct3D will not run. If I test functionality
using Microsoft's diagnostic tool (dxdiag), after hitting
OK button to launch test for direct 3D, it would
prompt "YOU HAVE CANCELLED THE TEST BY PRESSING A KEY"
even if I did not actually press any keys. Then tests
summary results to "TESTS WERE CANCELLED BEFORE
COMPLETING". This problem is intermittent, sometimes it
happens but sometimes tests become succesfull.

Please help me if anyone out there had encountered similar
issues to this or just anyone out there who have great
ideas of what could be the solution to this.. thank you!

bim b.k.