Lately my processor cooling fan has began to intermittenly make a lotof loud propeller type noise. Then just as suddenly will go quiet again.I thought perhaps the bearings were wearing out and went and bought a new Artic Cooling unit, but problem still remained same.I've since checked the bracket where the unit is clipped to but all screws are firmly in place and cannot see anything wrong there either.Have also tried enabling and disabling BIOS options that allegedlycontrol fan speed but this didn't make any difference either.Turning the case on its side seems to alleviate this somewhat butdoesn't get rid of it altogether. Any advice/solution greatlyappreciated.Regards

You're sure it's the cpu fan. Could it be the power supply fan? Here's an old mechanics trick. Get a long screwdriver. Place the handle against your ear. After grounding yourself, place the tip against case parts in question. NOT IN THE FAN. Where you hear the noise the loudest in where it's coming from. Be carful. I use this on car noises all the time.Bob

BobIt is definitely something to do with the cooling unit because I've hadthe cover off while it was happening and by applying some pressurewith my finger to the plastic fan assembly, the noise ceases and thefan resumes at high speed with its usual faint whirl. Likewise ifI gently tap the PC metal casing, but dont like doing that becauseit may do damage to the system in the long term. Will try thescrew driver tip next time it happens though.Thanks for the reply

So, you put a new and different type of cpu fan in and the noise is still there. Just seems like something isn't mounted correctly. The MB flexes when you push on it. Maybe something is too tight or too loose. I've gotten a little extra life out of oul fans with a little WD-40.Bob