iMac problem (power surge - hardware failure)

Hi sorry if this is in the wrong place, but it seems to be the only Mac hardware related forum.  I've had pretty good luck with EE before so I thought I give it another shot.

Anyway, here's the situation.  I have an iMac that I was working on that I believe had a power surge.  The result is a dead iMac, won't boot to CD-Rom and fried the harddrive.

The System:

500Mhz Slot Loading
Model M5521

Post surge symptoms and troubleshooting:

Computer turns on to Blank Aqua Screen
Harddrive clicking (definately toast)
Won't boot to Mac OSX CD

Things I've tried

Replaced harddrive (toasted it as well - started clicking almost immediately)
Replaced power supply (No change)
Replaced logic board (No change)

I still haven't replaced the harddrive again yet, as I'm just trying to get the computer to boot to Mac OSX CD (I didn't want to fry another drive)  Can an iMac boot to CD-Rom without a working harddrive?

I don't know a whole lot about Mac hardware, so I'm kind of at a loss as to what I can try next.  This is a clients computer so, and it was surged while in my possession, so I really need to get it up and running again.

What else should I try, what other hardware would I be concerned about after a power surge?  

Thanks for any assistance you can provide, and let me know if you need further details on anything.

JB