[PhIlLy ChEeSe]

Try un seating two of the three video cards(I know there on a loop) but it can be done without removing everything. Sounds like the controller on the board for the hard drives is borked or not enough voltage.
I know I'm saying this to you but(DO NOT BE OFFENDED!) Try the minimal approach, sounds as though a dieing PSU or memory stick? Remove the battery and do an over night Cmos clear.