Irritating buzzing noise

Seem to be plagued with problems at the moment. Have just fixed one and now the Sandy Bridge is making a fairly loud buzzing noise a bit like a doorbell being pushed. It is fairly intermittent and the sound lasts for a few seconds or for a minute or so. It doesn't seem to be related to anything I am doing at the time either.

Have tried tracking it down but seems to be nowhere in particular.

any ideas anyone please before I go stir crazy??

It could be Windows grinding a hard drive endlessly for any of several pointless, counter-productive reasons, and some hard drives seem to do periodic recalibrations or self-tests or something all by themselves, which I've observed to continue even after ejecting a docked drive from Windows. These things can last from seconds to minutes, and I can imagine it being described as "buzzing". Also check that fans are securely mounted and momentarily stop them one by one to rule them out.

Ok mate I'll try the fans as I only have SSD's hooked up right now

That's funny. My first sentence actually started, "If you have a hard drive in the system," but I deleted it as I thought it was overly cautious. As for other causes, motherboards can make whining sounds ("coil whine"), but I haven't heard it described as buzzing before. The PSU can also make whining sounds, and it usually has a fan that could buzz.

Strange that mate as your post started
"It could be Windows grinding a hard drive endlessly for any of several pointless,"

Oh ell whatever eh? Yes well this is very intermittent and some days may not be there the Corsair HX 650 I have never had a problem with so it must be down to fans I guess

The buzzing is a bit like those high pitched door alarms you get in shops definitely a piezo type sound.

I've seen noises that were not electronic, but mechanical such as a case door vibrating. I used to have a Dell Dimension E510 desktop PC and there was a plastic bezel around the front optical drives and USB I/O that would buzz occasionally. I had to stick something between the bezel and the case to make it solid and stop buzzing.

It could be coming from the speaker/buzzer connected to MB and BIOS is alerting you to an unusual occurrence like too high temperature, fan malfunction or under/over voltage. After a while cooling fans could get dry bearings and start to oscillate when right conditions are met and stop when their speed or temperature changes.

Yes well have looked around for any loose fittings and I think it is generated because it is so intermittent and a bit like Morse code?? I haven't heard it for the last three hours and I am now wondering if it is maybe the UPS which is not far away on power up that is when it seems to occur.

I shall dig out an old stethoscope tomorrow and use it to try and track it down and when I power up again.

Now I have an idea it may be the CPU temp warning going off as the Tcase of the i5 2500 is 72C and doing a full scan with the Kaspersky ran the temp to 65C which is unusual because any other scan only takes it to 40C