cpu fan stops working when xp loads. ibm thinkcenter. Fine in bios but as soon as you get the xp splash screen the cpu fan stops and doesn't start up agian. I don't want to ruin the cpu so I shut it down. If you go into bios and change fan settings to always on it seems fine but why would it have to change? Thanks for any thoughts. I have 3 of these and they all have the same problem. I help out with charities so I get these computers for donations so I don't know their past history.

if its possible to have the power supply checked and see wheither if that is the problem. another remedy would be to apply new thermal paste on the cpu if the it had any before. but do get the power supply checked unplug all the power connection and and use a power supply tester. such as pc/sps tester. can be picked up at any computer store that sells componet and hard ware and other bits of things also maybe check the battery. good luck Have a Great Day ;-D

Ignore it; some laptops won't run the CPU fan if it thinks it can get by without the active cooling.

Sorry I should have said the things I've tried. Its an ibm thinkcenter tower. A30 I took off the cpu and cleaned it and put new thermal paste on it. I also flashed the bios on one. The thing is that I have 3 of these and they all have the same problem. I haven't tried letting one sit because I'm afraid it'll burn out. Do you think they all got a power surge and messed them up? I can turn on legacy fan in the bios to force it to stay on but I'm a little suspicious about them when all 3 have the same problem. I don't want to give them a way and have them die in a few days. Thanks

Do you think they all got a power surge and messed them up? Doubt it; it's not exactly a direct route from the power supply to the CPU fan. I'm afraid it'll burn out. Don't worry, the chip reaches its peak temperature in under a second. If killing the fan wasn't intended, the computer won't last a few days. It wouldn't even last a few minutes.

I am downloading some updates and stranger still is that I noticed that the case fan also stops when xp loads. The only thing cooling the cpu is the psu. How can this be. I have been running it for 40 mins and its still going? Should I force the fan on in the bios?

As Razor said, leave it alone. When I cut my Pentium 2 on, my CPU fan runs full blast until I reach the XP splash screen, then it drops way down. I also have a "Fans always on" setting in the BIOS. I also have a Pentium 3 laptop that, as Razor pointed out, the fan comes on when it needs to. I've had it for 3 years and the CPU fan stays off most of the time. The reason why all 3 tower's CPU fans cut off like that is because they're all made to do cut off until when needed. If that weren't so, then there wouldn't be the "Fans always on" setting to change it. Every nation needs to realize that there's a God in Heaven that's one day going to have them give an account for their actions, regardless of religion.