re: I've had my Celeron 500 for almost 4 years. Nothing that major.
The cooling fan vibrates so bad I stuck double-sticky-sided foam tape between it and the heat sink. Now it only sounds like a muffled motorcycle engine. But no problems otherwise. I don't get it why other people have to upgrade at all, I've logged upwards of 60 hours/wk for nearly all of those 4 years and I've only replaced the hard drive twice. The only upgrades I've done were merely *adding* a hi-speed internet card and a CD-burner. Do you overclock your processor or something?
(probably just jinxed myself)