Today, my Mystic G4's power supply started making an out-of-the-ordinary noise instead of the typical. With the unusual noise, the case slightly vibrates as well. I could tell it was from the power supply, because I opened the G4 and felt it, and it was vibrating [a little, not an earthquake]. If I put it to sleep (stopping the fan) and wake it up, the strange noise goes away for like 2-4 hours. Is my power supply about to fail?

Here is a recording of the normal noise made

Here is the weird one

These are the specs on it:

1.2ghz Sonnet Encore (single proc.)

2GB RAM

400GB ATA Hard Disk

Geforce 6200 graphics/256mb

Two USB 2.0 cards, both 2-port

A Wireless N card

Delta Power Supply (I think this is more reliable than the AcBell one?)

This G4 has been in constant use since about mid-2007. (active 8-16 hours a day, sleeping the rest of the time)

Is the power supply about to fail? Should I try and vacuum it out?