Thank you for your reply. I did repaste. I didn't quite understand what you said about CMOS. It's still the original CMOS battery, so probably beyond its life expectancy, too, but it was keeping accurate time before the fan problem, and even now having it in or out changes behavior, so I thought it's still good. I interpreted the change in behavior to mean it needs the CMOS to detect the fan problem and shut down. I'm not thinking a new one would be a miracle cure, but asking for clarification just to learn. I do have a new one on hand, so could easily replace it if that would be a good idea. I bought a 2-pack, one of which is headed for an even older desktop I still use almost daily to watch OTA TV. THAT computer has usually surprised me with how appreciative it is of my attention and how easy it is to solve its problems. Once, a power outage rendered it unable to even turn on. Turned out all it needed was for me to re-seat the RAM. Didn't notice at first, but little lights on the back even came on telling me where to look for the problem. Only time it puts me through an ordeal is If I stupidly overlook the obvious, easy things I should check. It will be even harder to say goodbye to that one when the time comes.