Nvidia 7800 gtx problem

Seems like a weak GPU.....u may also want to check the ram for faults.....

I would replace the card unless if you were to clean out the dust and run the fan at max.

A small update, it seems that it is when i try to run a game (have tried WoW and fallout 3) that the computer is most liklt to chrash on me, i could hovever see movies in media player, surf the webb and such without any problems.

Now i am repairing windows XP and see if it makes any difference, if not ill format the drive and try to rebuild from scratch

Try the graphics card first. It sounds more like a hardware problem than a software issue--reformatting your hard drive is probably a waste of time.
It could also be your power supply, perhaps if there was a surge when the power problem happened. The PSU might be failing when you draw enough power from it (ie, under load in games and HD playback).

I am thinking the same, it feels more hardware related than software, the strange thing is how it manifest itself.

When i start the computer there is often the case that the powerup doesnt start at all (doesnt find keyboard, screen goes into powersave mode and so on), but if I restart a few times it goes as it should. Then I can browse the web, and basicly do anything with the computer (write, use media player, download, update, read mails etc) with one big exception.

I cant start any real games (small games as minefield and flashbased ones on the web is no problem) I can start them and gets about 2 min playtime before screen freezes (looks like it takes a strip of paint about 5mm hight and 2 cm long, and paints it all over again all over screen)

Its just my mind, but if it was power and/or Graphic cards should it always behave the same way (give me 2 min of movie and then freeze)?

Ill hold on the formatation of the drive, and will be most happy if i never have to do it.

Thanks for the suggestions and ideas, hopefully someone can give me a hint, i can not be the first one with this problem.