Johnny

Thanks for your reply... It does plug directly into the motherboard with a three-pin plug. When I removed the original fan, I struggled momentarily to remove the plug from the motherboard (before realizing there was a little clip that needed to be depressed). If I damaged that fan socket's connection to the motherboard, could that give me the symptoms I am getting? If so, is it repairable?

The error code on the blue screen when booting in Safe Mode is: 0xF8B4d528, 0xC0000034, 0x00000000, 0x00000000

The system is a Dell Optiplex gx260, which features a fan within a housing that clips to the inside of the case. Determined that after running for a few hours, the fan begins to get loud -- originally thought it was the hard drive dying, but opened it up to discover the fan was the culprit. Ordered a cheap new fan, installed and booted up. After the Welcome screen in Windows XP-Professional (this computer was a secondhand purchase from a local university) and clicking the user icon to log-in, the computer locked up on the "Loading Your Personal Settings" screen. Figured it had to be related to the fan, so put the old fan back in. Same thing happened, so upon another reboot, hit F8 to boot in Safe Mode. Selecting Safe Mode or Safe Mode with Networking results in blue screen with long error code, which upon Googling, discovered to be something related to drivers. (I know you may need that exact code -- will try to replicate when I get back to the machine.) Next, tried "Boot with Last Known Good Configuration" and finally got through the log-in screens. Once on the desktop, I adjusted the log-in functionality under Control Panel>User Accounts) to bypass the need to click to log-in. I planned to do a little testing to make sure everything was OK, then install the new fan again to see if it would work. However, the computer locked up a few minutes later. Shut down and rebooted a couple of times with increasingly quick lockups to follow, and determined that I'd have to use the F8>"Last Known Good Configuration" option to get anywhere. The last time, that method also locked up on the "Loading Your Personal Settings' screen (though this screen is slightly different than the original because I have now eliminated the user log-in screen). Ultimately, would like to put the new fan in, but error-free with the old noisy fan would be OK, too. Thanks!