[steve at Your Heaven]

Chris,
I'm sorry to hear you're having troubles. Since you physically removed all the other cards and still had troubles running, maybe a power supply limitation is not the problem. How about putting just the main HD card in the PC just to see if it works there, maybe even loading Protools too. A problem there would indicate that there's a problem with the card, rather than with the system. A short or near short in any card would overdraw the power supply, regardless of the supply or the total demands of cards installed.

As regards your loss of work, and if it runs ok, why not use it on the PC until you get the problem resolved on the Mac? At least you'll be able to get some work done, and physically switching one or two cards to re-test the Mac is not all that time consuming. I think you can load the Protools software on both machines, and all you'll get is an error message on the machine with the cards removed.

I hope this helps.