Could you do "push-ups for 2.5hrs.? That would be strenuous task and when it comes to gaming use, pretty much the same thing as you push until it breaks. You also found a simple cure at least for awhile, extra fan. That should have been long ago installed prior to any problems, because w/o it everything in that PC case has been working under "heat stress" conditions. Video cards are a weak link in such conditions and now it will only get worse, it's already too late. You may provide better cooling after the fact but it has become unstable and as you already know it's an older system, the effects of long use under stressful conditions has come at a price, replace and repair time. I'm sure if you replace the video card and get even better cooling would prolong use of that PC, otherwise its current "iffy" operation will remain. It will however work well in all likelihood under typical operation w/o heavy demand for the immediate future.
Graphics Card crashing during games.
OK my computer is a little old, However it's still working fine on the internet playing YouTube etc. However yesterday I Just yesterday I downloaded Arma 2 and starting playing it all good! Until today I loaded it up hoping to play it again but then the game(graphics card crashed) So I fitted an extra fan to the PC hoping it would maybe cool it down if it was overheating,This worked for about 2-1/2 hours however then It still crashed. The crash we are talking about is: squares just cover the screen then it No Signals and turns back on with a message saying "Graphics card stopped working and recovered itself" so i restart the game and about 10-20minutes later it does it again.. I can't seem to get a good long session without it crashing. Here are some stats Of my computer. 2GB Ram is old but should be OK because I am playing on the low graphics, this shouldn't make the game crash. I also gave it a dusting.
ATI Radeon 3600 series(Idle Temp - 41c)
Gaming temp - 51-2c)
Power Supply: ThermalTake 675w
Pentium Dual Core E6300 2.8GHz
1.4 TB Hardrive.
If there is a solution out there please provide it. I am upgrading to a decent PC soon but for now is there a way I can play smoothly?I want to try and do this without spending money because I am saving for the new PC.
Thanks in advance