In the past few years, 99% of the computer problems I'm having at home have to do with cooling, fans, and dust (this is also true for most of my friends). 3.5 years ago I purchased my current motherboard + CPU, after my previous' CPU's premature death[1] caused by a malfunctioning fan. Since then, I had many similar problems.
  1. The chipset fan stopped working, so at the lab they glued another one on top of it.
  2. A graphical card died because of too much heat.
  3. The CPU fan died, and I replaced it with a similar one (Thermaltake)
  4. The thermal paste between the CPU and the heatsink got dry and had to be replaced
  5. In the past months I almost never turn my PC off, because if I do, it's hard to turn it on - the CPU fan needs a CPR (of compressed air and WD-40)
Well, today I had a problem again - the PC got stuck and wouldn't turn on properly. Heat is an immediate suspect, so I brought some thermal paste from work, put a new layer on the bottom of the heatsink and sure enough - the PC works. Damn it, so much advanced technology in these computers, and most of the problems have to get caused by heat removal. This is simply annoying. [1] Thankfully, modern CPUs don't simply die in smoke and flames when they get overheated. Rather, a temperature monitoring mechanism causes a shutdown if the temperature is too high, and then the CPU gets stuck. And if the problem persists (which is usually the case with mechanical problems), you have a technically alive but non-functioning CPU.