Hey Mark--

I agree that the culprit is most likely the fan. You don't indicate whether your computer is a desktop or laptop. Replacement will be easier if a desktop.

The main thing to keep in mind is that you will almost certainly need a specific direct replacement fan, since almost all fans used today contain either a temperature sensor or a tachometer sensor (sometimes both) that send(s) information back to a dedicated connector on the motherboard. In a laptop, the fan generally mounts directly to a "CPU cooler," with specific mounting requirements and similar connection requirements.

There used to be a business in Dallas that specialized in computer fan replacement. I haven't found them yet via a search, so they may not still be around If you have a MicroCenter or similar, you might be able to work a deal where they order a fan (prepaid) through the service department.

By the way...disconnecting the fans may or may not work. Some motherboards will sense for fan operation and shut down if they don't see confirmation that the fan is connected and operating. I once had a small form factor ("cigar box") PC that would not even start up when a fan failed.

This is a pretty common repair issue for "experienced" PCs, The only question is whether parts are still available, pretty much like for cameras these days.