Is my PSU dying?

I just moved my computer, and when I plugged everything back in it started making a very high pitched noise. This noise was very quiet and on the very edge of hearing range. The noise was produced when the PSU switch was on, but the rest of the compuer was off.

At the moment I am thinking that such a high pitched sound is caused by vibrations in the PSU's transformer, due to AC voltage. Some part of it might have been jolted into a looser position by the moving.

Anyone else have any thoughts? Is it worth buying a new PSU to be on the safe side (assuming the noise doesn't go away). The last thing I want is a loud pop and some sparks inside the tower...

Help much appreciated.

I guess it is possible, hard to hear through text. Sometimes it's something other times not. Please describe you idea of moving. Is it, (A) Moved the PC as if I was carrying a sealed vial of Nerve Gas. or (B) Moved PC as if I were practicing to be a baggage handler at LAX. I mean if you were doing "G" testing on your case then yeah that could do it. But since more then likely it is (A) then Check the voltage at the plug first. Since the you moved the PC, the power at it's new home may be sagging a bit.

my Thermaltake did that before it died. But it was a constant high pitch even when the computer was off

Maybe the transformer for the +5V standby section of the PSU finally cooled down after running continuously for months or years, causing its core or coil to shift around. Some PSUs have two small transformers, others only one. Another possibility is that the low voltage filter capacitor for the +5V standby has gone bad. If's often located near the transformer, next to a 1/4" diameter diode.