Perhaps it's design is to turn on at a specific temperature. It would be easy enough to force that and observe the fan operation. You can also direct another source of cooling air into an opened case to see if that helps. It has been known that some drivers don't work properly on some systems and returning to a previous version helps.
Please help, im stumped!
Last week my computer started flickering, and had lots of little green dots all over while playing Half-Life 2, but when i quit to windows everything was fine. Tonight it did it again, and then my computer crashed. while rebooting it would show bios and bootup screen just fine, but then once it tried to enter windows it would just restart. It kept doing that so I booted safe mode, and was able to do a virus scan, but nothing turned up. So i reformatted my system drive and reinstalled windows XP. everything went smooth, until i downloaded and installed the latest drivers off nvidia website. once they were installed, the computer wouldnt go into windows anymore. I went in safe mode and uninstalled the drivers, and was able to get into windows again. Is my grapics card dead? It seems to me like it has died, but i dont want to buy a new card and find out it was something else, like the power supply not putting out enough power. The card is a Gigabyte 7950GX2, and has been working flawlessly for a little over a year. When i pulled the card out of the system i left it plugged in and powered up and the fan didnt move, but i dont even know if the fan runs unless in 3D. im stumped, anyone have any ideas? thanks a bunch for any help!!!