Eli Bendersky's website Yesterday my computer died. Again.
The single most popular PC ailment I've suffered from historically is failed fans which caused burnt CPUs, chipsets, motherboards, etc. On one notorious occasion I had to replace my whole motherboard, CPU and memory because of a malfunctioning CPU fan. And this is what I suspected yesterday, since my CPU fan wasn't working well. I brought it back to life with WD-40 but the PC still wouldn't start, so I already accepted the sad fact that the CPU probably died (AMD CPUs have one big disadvantage - no normal thermal shutdown feature). When I turned the PC on it would just repeat one long beep and wouldn't even turn the screen on.
Luckily I decided to double check before heading to the PC lab. I checked what the beep means from my parents' PC when we visited them for lunch, and it turned out (from a couple of sources) that it probably means a memory problem, rather than CPU.
Strangely, it helped. Once I moved one of the chips around to another slot, it started working. So now I have my PC back again, without the need to do a costly upgrade.