front power button

Hi All, this is my first post here though I’ve often arrived here when searching for troubleshooting answers. I have a Mac Pro 2008 (3,1) that I bought new for research originally. It lived it’s life doing day to day tasks while running simulations that took sometimes days in the background...

I put the computer to sleep, when I try to wake it clicking the mouse a relay clicks from the back of the computer where the power supply is, but the hard drive doesn't spin up, I put my hand on the drive. I tried booting from my backup drive with the same results. I press and hold the front...