hi all, lately I have been experiencing a subtle noise coming from the pc that sounds very much like what you'd hear when putting your watch up to your ear, tick tock type noise.  It is so subtle that I first thought I had a watch somewhere lying around in my office...took me weeks to figure out it was my computer.
 
My first thought once I recognized the noise, was to assume my HDD needed to be replaced (aka the Click of Death), so I went ahead and did that.  Unfortunately, the noise continues.  After listening more closely I think the noise is coming from the power supply.  For what it's worth, I have run Speedfan and HW Monitor and both tell me that my temps and voltages are in normal ranges.  I did just have a spat where my PC wouldn't turn on after trying to find out what the problem was (it would spontaneously turn off when I placed the left side panel on to close it up), but now the PC is running again along with the occasional tick-tock.
 
Has anyone encountered anything like this, or able to explain what it might be?