I then got my first indication that I might have done something wrong: a visible plume of dust was expelled from the back of the computer. It booted up fine, no warnings or anything like that, and the utility SpeedFan (which monitors fan speeds and temperatures) doesn't show anything wrong either. But I did notice that the computer was running a bit louder than before, and between that and the dust plume I got worried. I did a search on the proper method to clean a computer with compressed air, and one thing it mentioned was to be sure that you were blowing all the dust out of the computer and not into it. To be frank, I'm not sure I did that properly. So I decided to shut it down and repeat the process, focusing especially on the power supply, the fan on which seems to be the louder one.
Here's where the second indication came in, and got me scared enough to post here asking for help: as soon as the computer had shut down and the fans began to stop, the computer started automatically rebooting, the fans roaring for a second or two, after which it seemed like any other reboot. I tried again, this time making absolutely sure to push "Turn Off" and not "Restart". Same result. So I did a search on automatic rebooting after shutdown, and came up with overheating as a possible cause. To me, it seems the most likely explanation is that I accidentally blew dust into my power supply, and the fan on it is now barely keeping up with the heat produced. Either that or the compressed air damaged the fan somehow, with the same result.
Now, I could turn off my hard drive's write caching, go into the near-shutdown part, just pull the plug, then proceed with the cleaning. But I'm afraid that if I do that, the power supply won't have any way to cool itself of the residual heat and will suffer permanent damage. What do I do? My computer seems to be running fine now but I don't think I can shut it down, or that it can stay like this indefinitely. Please help ASAP!
Edit: forgot to include the other reason I've settled on the power supply as the likely problem: SpeedFan is reporting normal temperatures for the CPU and graphics card, but as far as I know it doesn't monitor the power supply. I hope I get a reply soon, I think the fan might be getting louder...
Edited by ConstantVariable23, 14 April 2010 - 03:58 PM.