Hello,
I have nvidia 8800GTS 320mb from Point of View EXD edition (overclocked from factory).
It served me well for 2 years but now I have problems.

I've entered a game played for few seconds and got artifacts, so I exit the game lowered the graphic settings and entered again, still got artifacts, so I exit, I didn't play any game till the evening but the pc where on.

After about 6 hours I've entered another game and then my pc stuck with odd lines on the screen.

Now I have lines and dots from start up and even in bios..
and in safe mode and VGA mode too..

Is this only video card failure or could it be more then that? like mother board or I don't know..
And could the source for this be a virus or just over cooked?
Because then I will just buy a new card as my warranty run off..

Thanks alot,
Lith

P.S:
my pc:
Windows XP x64 bit
Q6600@2.4
Nvidia 8800gts 320mb
2GB ram
Asus P5K mother board

Try updating the drivers:

Updating the drivers was the first thing that I try, but the point is
that its from the start up, before the windows or drivers are loaded..
so its not it..

oops, I missed that

Remove the Video card, and using high compressed air can (purchased from electronic and computer stores) blow out all dust in and around the card
Some of these 3D cards have heatsinks that you can remove (some easily, but not all) You can also re-thermal paste the chip onboard the card

I did it already the day it happened I will try do it better though I didn't remove any parts of it :/, thanks for the help :P
But do you think that the source to this could be virus or something else?
Because if I buy a new card I don't want it to be damaged by the same thing..

Try This
Video here
Seems to be a common issue with G80 gpus. If you don't wanna try it sell it on ebay and someone will buy it, and they will bake it.
As always your success will vary if you decide to try this. Worked for my 1950gt when I got the nice acid trip lines