Gfx Trouble!

[Doomulation]

Okay now, I'm in a bind here, see? The source of the problem is the gfx drivers. Of this I am sure. I've tried to install several versions of the nVidia detonator drivers, with the same problem, however. The problem does not occour with the default XP drivers. It is clear to me that it's nvidias drivers that causes the error. Unfortunaly nvidia offers no damn support for their drivers even (afaik), so I turn to you...
Here's the problem:

The screen tend to go black and then normal again at random intervals. Not a serious problem, I know.
However, after more random time, it completely loads the computer (can't do anything but move the mouse!) The screen flickers like above time and again and never stops. I can't do anything when this happens... just... reboot the computer. And that causes all sorts problems.
Hard disk errors... unsaved work gets lost... unfinished downloads (if any)...

I have no idea what is causing this. It started sometime after I installed service pack 2. Thinking it was the problem, I uninstalled it. No change. So I reinstalled windows (advanced/full install; no stinkin' upgrade or something). Still no go. HOW? WHY?? That should fix it, shouldn't it? The XP installation is clean (no service packs slipstreamed). I recently re-installed sp1, yet no change.
Okay, I'm clueless... sigh.

 

[buda]

I’m probably wrong but it might be that your power supply is causing all the problems. Does your video card connect to it for more power? If it does than its possible you’re your power supply just can’t handle it. Do you have a stronger one, or know someone that has a better one just to test out and see if that is the problem?

 

[Doomulation]

I doubt that would be the problem. In 3d games and other requiring 3d applications everything runs fine. It's just under windows GUI that this happens, for some strange reason.
But still, it did work alright all since recently and I have not upgraded this computer for some time, now.