PC Making Extremely Worrying Noises From The Inside

Yesterday my PC started making loud & extremely worrying purring noises from inside the case. It has NEVER done this before & I don't know what the problem could be. I have no malware or viruses etc on my PC and I've checked the temperatures of the components & they're all fine.

I even opened up the case to check whether any of the leads were getting caught on the fans but that's not the case. I don't want the PC to just blow up on me as I've spent a lot of money on it.

My PC specs are as follow:

OS - Windows XP Pro
CPU - Intel Pentium D 2.8Ghz
RAM - 2gb DDR II
Video Card - 256mb Nvidia Geforce 7600GT
HDD - 2 hard drives (1 with 40gb & 1 with 320gb)

When I bang on the side of the PC the noise stops for about 10-15 minutes though. Obviously I don't want to have to carry on banging on the side of the PC incase anything gets damaged.


HK

 

The most likely cause is a fan.

One way to check that out is to open up the case and start the machine. If your head is close enough to the open side of the case, you may be able to tell which fan is causing a problem. But that's not likely, given the way that noises bounce around in the case.

Touch each fan with the eraser end of a pencil right in the center of the hub. The idea is to slow the fan down a little. You don't need to stop the fan -- that will cause it to draw more current, which could damage the fan or the circuit that supplies power to it.

Don't forget to include the fan(s) in your PSU in your checks. If you can't get into a position to touch the center of the fan hub, you could try lightly touching the spinning fan blades with something soft and flexible, like a small paste brush.

When you slow down the fan that's causing the noise, the character of the noise will change.

Replace the fan that's gotten noisy. Noises of the kind you describe usually mean that a shaft bearing is in trouble. When it fails, it will usually stall the fan -- again, causing it to draw too much current. That might take out your PSU too. If that happens, a $10-$15 replacement job has become a $50-$100 replacement job.

 

If you find that a fan is not responsible, the next suspect is one of your hard drives. Shut down the system, disconnect one of the drives, and re-start. If the noise doesn't re-appear where it normally does, you've found a dying hard drive. Back up whatever data is on that drive that you want to keep, if you haven't done that already, and replace it.

Again, the likely cause is an impending bearing failure. Get the data off it before it goes.