I'm not too sure of why my computer does this or where the sound is coming from but my computer appears to be making a buzzing noise. Could it be the fan, motherboard, graphics card, bios or the power supply? i have no idea. Has anybody come across any similar problems? When i turn the plug off at the socket then the noise goes away however if i leave the socket on and turn the power switch off at the back of the case the sound remains. I would appreciate any help I could get on this because the noise is driving me round the bend at night.
If it buzzes when the power is turned off at the back of the power supply, it can't be anything in the tower itself. To be honest the switch should normally be right next to the input plug (electrically as well as physically), so I would have thought that what you say is impossible. However if it's anything, then I can only see it being the PSU.