6800GT Crashing in Games! HELP!

[LostPuppy]

Before i get flamed i would like to mention that i have been to this thread http://www.nvnews.net/vbulletin/showthread.php?t=32759 , it took me 4 days of study breaks , but i finally finnished reading that entire thread and was able to conclude that wasnt the thread for me.

Whenever i run games (weither its hardcore BF2 , or some not so demanding game a friend wrote) after 10 min my graphics fail. at first the game starts to get "fragmented" like i can see white polygons and lines in the screen. and then about 3 min after that starts the whole thing just crashes (the screen becomes an assortment of ****ed up colours) and i have to push the power button on my tower to restart.

I have a p4 3G , 1G of RAM , and the 6800 GT, nothing is overclocked.

Like i said i went to that stickied thread but most of the people there are having problems with it freezing for a few a seconds. which isnt my problem , although mine crashes , it never freezes then comes back. Some people in the thread did say they had "crashing" so i read the entire thing anyway and tried about 7 or 8 of the recomended fixes like changing drivers and turning of FW and so on. none of these have worked.

help please?

[ynnek]

real time load temperaturesboth gpu and ambient - too high?
psu not keep up with power demands
card itself just flaking out

or possibly other hw issues, although i doubt.

[LostPuppy]

how do i test the psu to see if it is the problem , i got it a year ago for last christmas, its 600wt

EDIT: other then just feeling the air coming out of the fans , is there an app i can use to check my cards heat?