No end user diagnostics. While I would have A. Tried the old power supply, B. Always get more Watts in the next PSU and C. Replaced a failing fan, the ONE THING I CRINGE at is your use of the cleaning cloth. The chances it had high electro static potentials means that all bets are off.
Try the old PSU.
So i just got back from a tour in iraq and my desktop stopped working. my family said it broke while i was gone. i came home to inspect it and when you turned on the computer it made a high pitched whineing sound from the power supply. i had a 630 watt raidmax power supply. i knew it was not supposed to whine like that so i took it out and threw it away. went to frys and bought a new 600 watt power supply by corsair. i installed it and turned on the computer and it ran for 3 seconds then shut off. does this everytime i start it! it dosnt make the whining sound anymore so i know the old power supply was bad. but computer still wont start up! i am wondering what the problem could be?