Video gets lines, then shuts off and locks up

Lately my computer seems to freak out when I play any 3d game, or watch some movies.  What'll happen is everything will seem normal, then horizontal lines go across the entire screen, and if i don't close whatever app thats causing it in 2 seconds, it shuts the screen off, and locks up.

I've done all I know to try and fix it.  Removing/reinstalling drivers, using different ones, turning down settings, anything i can think of, but it keeps happening.  Does anyone have any idea whats going on?  I'm running XP sp2, with a TNT2 64.

I have noticed that heat seems to be a factor, but since i put an AC in the room, it's been mostly fine.  But it just randomly tweaked out tonight.

Well, if you noticed that temperature is an issue, it'd be reccomendable to take the side of your case off and give it plenty of ventilation for a while, and try to re-create the situations where it gives you trouble.

There might be a problem with the fan/heatsink on your card. Check that, and make sure it's firmly seated.

Also, if you are in an even latitude remove the case from the right side, otherwise remove the case from the left. Most short-circuits are caused by not following this very simple principle.

>>3

Wait, what?

Well, I opened it up today, everything is in order, and it keeps doing it.  Seems to be when i first power on and start up.  after the second loading of windows (no power shut off, just restart) it seems fine.  For example, it did it just now, but with no warning.  maybe it's just time for a new comp anyways.  this one is way old

okay, problem solved.  turns out that particular video card and this motherboard don't play well together.  swapped out another one, all is well