I am trying to fix my Nvidia 9800 GT right now (I know its old but I can't afford a new one right now).
The problem is every time I go start up a game, even on the lowest settings, it crashes after about 30 seconds (give or take). After running it would be very hot.
The first thing I tried was cleaning out the fans and the card itself, but that didn't work so I downloaded Speedfan and tried to get the fans going fast (but they already were). I found out that the card was idling at about 87 C.
Next I opened my case and had a fan blow into it. Now it is idling and running in game at about 57-60C. After I put the fan up it crashed again right when I started, so I used Driversweeper to get rid of all the drivers and I reinstalled the most recent driver and tried it again (with the fan still up) and it seemed to work fine on absolute lowest settings. I let it run for about 15-20 minutes starting in windowed mode and moving up to fullscreen. After a while I tried cranking up the settings and it immediately crashed again (with lots of square patterns, black and colors, like usual).
Windows 7 32-bit
Inter Core 2 Quad CPU Q6600 @2.40GHz (4 CPUs), ~2.4GHz
6 gigs of ram (ya I know I cant use it all in 32 bit, gonna upgrade eventuallly)
and of course the Geforce 9800 GT
Also my power supply is an Orion Model: HP585D with, I believe it was 485 watts
I dont know too much about graphics card related issues and could really use some help on this. It would be nice to get it to work, instead of waiting to buy a new one.
I have been testing this on GW2 but it has crashed on a number of other video games in the past (until I just took it out), including old roms at one point (but never videos).
Did you ever get a resolution to this? I've had the "squares on the screen" problem from beginning (since card was new). It doesn't always appear - typically, only in some games - primarily NWN2. Recently, I installed Ubuntu 12.10 and the squares show there almost all the time.
For me, they are a pattern of square areas within which is another pattern of square areas composed of wavy lines of green (usually) or purple lines.