Last night my Dual G5 decided to stop working. It's similar to the problem that my old (well, not THAT old) work G5 was having. That one went to the repair center three times and they couldn't get it to duplicate the error. The final solution? Plug it directly into the wall instead of through the power strip. It seems it needs more power than it could get through the strip.
The same problem happened to my coworker Scott's new G5 iMac. Plugging it in directly to the wall fixed his too.
The similar thing between all three of these computers? They were purchased through Mac Mall and they came with a free RAM chipset in addition to the Apple memory that was included. Possibly the extra RAM is failing and it needs to draw more power as time goes on until the strip can no longer provide it. If that's the case then it's just a matter of time before the component totally craps out.
So, tonight when I get home I'm going try plugging directly into the wall and see if that fixes it.
Right now I'm still under warranty if that isn't the problem but I really, REALLY need to splurge the $300 to get the extended Apple Care Warranty before my year is up.