I would like to point out that AMD only made the processor. Theres a lot of other things that could be going wrong inside your computer. (ie. Hard drive failure, mobo going bad, power supply gone, corrupted files in the operating sys, virus...)
Also, processors are designed to function for approximately 20 years. although its hard to imagine having a computer that is 20 years old. Bottom line is that AMD does make a good product, if they didn't, they would be out of business.
BTW, What kind of processors are in your older computers?
Lian Li Aluminum Case
Intel D975XBXK2R Mobo
Core 2 Duo E6700 CPU
EVGA 8800 GTS Video Card
Corsair XMS 2 x 1gig RAM
Zalman 9500 CPU cooler