weird computer sound. For some reason, my computer will produce weird sound once in awhile. It happens lately, it sounded like something is vibrating. It's not quiet sound of cdrom or hd access. I wonder what could be the cause of this?

Probably a fan going bad. Stick a pencil into each one to see which it is and replace it.

Don't ignore the problem! A fan that makes noisy will usually stop before too long. A fan that stops can cause serious damage to your PC.

How can I test which fan? I currently have cpu fan, a PS fan graphic card fan and a case fan. HOw can I test them? I thought it could be HD problem, but I guess I was wrong

Q. "How can I test which fan?" A. "Stick a pencil into each one " The one that quiets down when it can't move because a pencil is in it is the one to replace.

Hard drives make this dull "ca-clankey tick" sound, its usually an early warning that its going to fail in the near future. Back up data, and replace it fast! Also, if you stick a pencil into each one.. omg.. Fans don't make noise unless the armature is making the blades hit the walls of the unit. Then its a continual "buzz" sound. The hard drive clicks usually when its trying to read, but usually is never persistant with the noise. Not to mention, some higher rpm fans can get damaged if you start pokeing them.. Just unplug em one at a time, try to avoid the one on the processor if you can.

I was going to say, I would unplug all of your other fans before unplugging a processor fan. usually that means overheating the CPU. If it is infact your CPU fan, assuming your is still a P3 fan. The sound of a fan like that sounds like when you take a ball-bearing wheel and spin it really fast and it immediately rattles and makes that sound. (couldnt think of another description) If that is the case then you porbably ought to get it replaced SOON.