Power Mac G5 continuously restarts on its own

I have a PMG5 that started restarting continuously on its own. I have ruled out hard drive issues and memory for the following reasons:

1. Moved RAM to different slots, swapped around, made no differences.
2. Ran ASD disk in software and firmware modes, everything passed.
3. Reinstalled Server multiple times, made no differences.
4. Swapped a replacement HDD that I know works, re-formatted, installed OS, made no differences.
5. Tried booting from Bay #2 with a cloned OS, made no differences.
6. Ran Disk Utility and repaired disk, and repair permissions. The permission repair had a lot of unexpected error that were not corrected, hence re-installation of OS.

The PM boots from the Server install disk, as well as the ASD disk. The only condition that occurred simultaneously to this problem starting was a new memory battery after the original one was depleted. I'm completely baffled at this point. I have not tried installing a client version of 10.5 yet. Each time I install a fresh Server, it will restart into the 10.0 OS. Upon updating to 10.5.8 (or which ever the last version was that Software Update downloads from Apple's server), it will download and install, but upon restart it gets to the gray apple on the gray screen with the spinning gray wheel, then restarts on its own... over, and over, and over, etc.

I don't have another memory battery to swap with the new one, but find it difficult to couple the two scenarios together.