Cat Hair and computers don't mix
I was picking up a desk for my little one from a lady who was moving to a smaller apartment. When I got there she asked me if I'd like to buy her CPU as well, for parts. I asked her what was wrong with it, and she said it stopped working. First the floppy drive went, then the CD-Rom went, then it kept turning off on its own. Thinking $15 would be a bargain for another 512 MB of ram, I said what the heck.
The only other time I've ever seen that behavior happen was in one of my industrial computers, the cooling fan would drop out from time to time, and the power supply would overheat and quit. Thinking it was something similar, I opened the unit up expecting to find a weak fan.
Instead, I found a massive tangle of white hair and lint. With the amount of cat hair in there, you would think her cat was bald. Anything opening that was supposed to let air thru was completely plugged with cat hair. The heat sink on the processor was completely plugged with cat hair. I had to put a credit card inside the floppy drive and pull out cat hair.
If you've got a cat who loves to spend time near your computer, I'd recommend vacuuming it out every so often.
Needless to say, the broken computer I got for $15 is fully functional now. I almost feel guilty, but she set the price, she had already replaced the computer with a new lap top. I guess I'll leave the memory alone and replace my kids old Pentium 2 machine.