It sounds as if your CPU fan might be going. Inexpensive to replace. I would try that first. Power supplies are usually very durable, particularly if kept clean - no 'dust bunnies'. > Hello. My computer is a Dell Dimension 8100, P4, 1.4Ghz, 384mb mem, > 40Gb HD. I have virtually let this computer run non-stop since 2001, Visit our website regularly for FAQs, articles, how-to's, tech tips and much more http://freepctech.com