I have a Dell precision T 5500 workstation. I recently installed 2 fans in the rear of case. 1st was OK because I tested with just 1. After installing 2nd the pc didn't want to turn on but finally did, but hyper threading was disabled. I went into bios to unlock hyperthreading and it immediately crashed. The Psu is making a not too loud clicking sound when I try to turn it on but can't even get it to the 1st screen, I hear the hard drIves starting to kick on and then it switches itself off again. Sounds like a definite bad power supply I know but was hoping someone could suggest anything else. The immediate shutdown after hyper threading has me a bit worried. Not a pro here, Please Help!!