At last some company on this thread
, I've learnt from your another post that your equipment setup is quite different than mine (I have GeForce 2 + VIA board). This is a kind of relief to me, as I was starting to think this problem has something to do with my hardware configuration - but apparently it does not.
Still, it doesn't mean it's not a hardware problem, but I don't even want to think that my adapter or AGP slot may be malfunctioning... I hope this is not the case.
I also experiance occasional blank-screen lockups even not running any kind of 3D or video software (just usual desktop apps).