I was happily working (read : playing games online) when a little window popped up : CPU temperature critical - Sytem shutting down.
I clicked cancel while I reached under the desk to get a quick idea of the seriousness of the warning. The machine was hot, but it always is. I checked the PSU fan - because it wouldn't be the first time that one fails - and it was working fine, and a noticeable flow of hot air was exiting from the casing. The warning popped up again : CPU temperature critical. System shutting down. I quickly maximized the system monitor and there it was, blinking in red : CPU temperature at 71° Celsius!
I once again cancelled the warning while rapidly closing whatever windows and applications I didn't really need. I dropped my internet connection, close the usenet reader, browser, local proxy/spamfilter(s), RSS reader and who knows what else. In the mean time I was also checking whether I could get the side panel off the box to let some fresh air in and see what the problem was. After all, a CPU normally doesn't overheat without good reason, so I figure the cooler must have fubar'd. However, the noise coming from the machine was quite normal, and I guess I'd notice if a fan wasn't working.
Crap - for once I actually had screw in the back of the panel and of course no emergency open heart surgery tools were to be found nearby. In other words, I was looking for a screwdriver. Nowhere! I usually have one somewhere on my desk, hidden under whatever may be on top, but not today. I finally scrambled for my toolbox and yes... a screwdriver. By the time I found it, I had also started a manual shutdown procedure for the machine, not willing to take any chances. The last thing I can use is a fried CPU!
All of this happened in under 20 seconds, but by the time I was able to get the side panel off, the machine had shut down so bye bye chance to actually see what caused the problem in the first place. Aaargh! Anyway, I turned it back on, grabbed my vacuumcleaner and sucked away all the dust I could find inside. I grabbed a flashlight and checked all coolers inside (CPU, Videocard, overal system cooler, PSU fan, Motherboard fan, and I probably missed some others) and they were all happily whirring along. Strange...
I grabbed my small drill and cut some extra holes into the front panel for good measure - although I know very well that won't affect CPU temperature, in a best case scenario it may lower overal sytem temperature a tenth of a degree - and reassembled everything. So, now I still have no clue what occurred just there, but at least I have a clean PC now. I also tied up some cables to optimize airflow, but that was more a "make sure no cable can get stuck in the fan and slow it down" thing than anything else.
While you were reading this, you were just drawn into the story, weren't you? You were waiting for the next cliffhanger, the next high... I know, I can make opening and cleaning out a computer as exciting as a blockbuster hollywood action movie. Not that those are anything to measure up against but hey... I try!