Hi, when I bought my PC two years ago, it was silent, it barely made any noise. However, I later made a huge mistake. I opened the case to clean the inside of the computer with an air compressor, but while I was cleaning the fans I wasn't holding them so the air compressor made them spin faster than normal. Following that, every time I boot my PC now, it makes a loud noise and also the PC makes a lot of noise in general. A lot more than when I bought it, to a point where sleeping next to it when it is turned on is a hard thing to do. Now, I'm wondering if that mistake is the cause of the noise. When I look at the fans, they don't seem to be damaged at all. I have 3 fans: The case fan, the graphics card fan and the power supply fan. My PC is cleaned regularly so I know it's not dust or anything that's causing the problem. Here's some interesting info: It only makes noise when it's booting after the computer has been turned off for more than 30 minutes. If it's less than that, it doesn't make the loud noise. I have no idea why. Also, about 3% of the time, the desktop doesn't get to fully load because the computer freezes. It's a problem that started at the same time the noise started. If it is indeed one or multiple fans that are broken, how can I know which one(s) is? I made a video of when I'm booting the computer so you can hear and see what is happening. http://www.youtube.com/watch?v=yX2fkBh5zZE Thanks for reading.