I have an old desktop that is running with an Athlon 2200 chip. I recently noticed it was overheating, so I took it apart and saw that there was a lot of dust and fuzz inside, so I opened it up, vacuumed the case, and installed a new CPU fan (and pulled the CPU) After that, the BIOS is now showing the CPU as a Sempron 1800, not as an Athlon 2200 (which it was before).
Any clues? Did I mess up the BIOS? Or did I accidentally clear a jumper I shouldn't have? I don't think that I did anything like that, but I'm not positive.