I was looking at my parent computer they have had for years because the fans were making a lot of noises. When I opened it it was dust galore. I was also curious which fans were making the noises. So I started to unplug them and the computer was silent. So I plugged the fans in and restarted the computer. I didn't have time to clean it so I would do it later. However the next day the computer would not turn on. I spent a few hours looking at forums trying to figure out why nothing was happening. Since I caused the problem I knew I would have to fix it.
I looker on forums on why their computer would not start and tried any solution that I got. I even went so far and took the PSU out of my computer and put it in their. Still nothing so I wanted to make sure the computer wasn't fried so I took out their ram and luckily their computer started to beep.. Then I had the idea to retrace my steps and I plugged out and in the fans espically the CPU fan. It worked and I was so happy. So I put their computer back together and I runs fine. If your curious yes I did clean out all the dust.
If you are working on someone else computer take all precautions. That why I got the new toolkit so I can work on mine and other people computer safely.