When I turn on my computer, about 3 to 5 seconds after it is turned on, and when it is going through the memory testing, the computer emits a constant squealing noise, which is coming from around the gpu/cpu/psu area (its hard to locate, but its definitely not from the hard drive). It doesnt sound like a mechanical noise, so I dont think its the fans. It usually stops after about 5-10 seconds and continues to boot, but some other times its doesnt stop and the computer becomes frozen while still testing the memory, and some other times there is no noise at all, and it boots fine. I have had this problem for about a month now.
The most recent hardware change i made was a new power supply and graphics card and totally new RAM about 6 months ago, and havent had any problems until now.
I am running windows xp home (32bit)
-ati radeon HD 6700
-amd athlon 64 X2 dual core
-4Gigs of DDR2 ram
-PSU is around 650W (cant remember exactly, but I do know it is enough to power all components)
You can disconnect the case fans from the case, keep them plugged in, and run them outside the case. If it is one of the case fans it will be much easier to determine which one with them outside the case.
You completely sure it's not the hard drive? They can make some strange noises when they start to fail. You can run the hard drive outside the case also to make sure that's not it.
Could also be the fans on the cpu and graphics card, though those will be a little harder to isolate. Make sure no wires are interfering with the fans.
edit: had another thought. Could be coming from the motherboard speaker, yank it out and see if it stops.
Ah you were right about your suspicions on the hard drive. I just opened up the case and I put my ear beside it and sure enough it was the source. I was mislead earlier since I just listened from outside the case and the sound was louder near the back.
How much time do you think I have to transfer the files before it completely fails?
The problem with mine was actually a bad capacitor on the motherboard, you can usually tell if a capacitor is bad if the top is slightly buldging out and/or there is a small amount of brown liquid leaking from the top of the capacitor. I would take a close look at all your capacitors and compare all them to see if one may be buldging out from the top. If that is the problem you may have a bit of trouble finding a repair shop to replace a capacitor cuz they fear it may have already damaged the motherboard, but you'll find one, and I'd say go for the replacement capacitor, it's pretty cheap, mine cost $20 to replace and my computer now works fine ever since.
If you can't see anything wrong with capacitors I recommend trying suggestions above.