Q: I've had my computer working for 3 years now and recently i bought an 8800 nvidia graphics card and put it in. So roughly a month later after playing my computer it froze and i restarted it, but the monitor wasn't turning on. I then took the entire computer apart and cleaned everything and let it cool down. When i start it now it stays on for like 40 seconds and then shuts down. I tried taking the 8800 out, taking my soundcard out, and disconnecting my cd rom drives so that there wouldnt be too much power usage but the problem persists. I would like to add that i removed the cpu and cleaned the fan and then put it back in. The fan seems really secure to the cpu so i dont think the processor is overheating (even though the computer acts like it is)
A: there was thermal paste under the fan correct? and it was not dried out... you failed ot mention AMD or Intel chip Intels have a far higher heat tolerance than AMD chips as for PSU test unplug everything, even mobo header connector turn off the small switch at the back of the PSU ( unplugg PSU if no switch ) get a small insulated wire, about 2 inches long, strip about 1/4" of each end see the green wire in mobo connector make a small jumper to the the next black one ( blacks are ground , green in ready to power signal line and always has power on it with PSU off ) with the small wire you got, make sure it makes contact with the pins to the mobo connector. no power up ( or plug in ) the PSU, it should turn on and stay on, if not you got a bad PSU