HP DL380 G7 Will Not Power On

We have a similiar issue to a few other people on here, although nothing we have tried has led us to a solution. We have an HP Proliant DL380 G7 that will not power on (most of the time). Here's what we've seen happen with it:

• After a power down (usually power failure), power light stays Amber when pressed, no fans or any action. PSU fans are on, no lights on PSU.
• Power button is pressed, server powers on, performs normally. (has only happened once or twice, stroke of luck?)
• Power button is pressed, server powered on, but very quietly. Normally sounds like a hurricane on startup. Took awhile to POST, but never initializes hard drives. They never power on, so server cannot boot.

Here's where it gets interesting. After the last bullet happened, we turned the server off, then on again. Upon turning the server back on:

• Power light turns green
• Hard Drive lights all Flash like they are being checked.
• Server power cycles after ~1-2 seconds.
• Rinse and repeat

That last case has happened twice, most recently. We've tried flipping the System Maintenance DIP switches 6, and 1,5,6 with no luck. When we try this method, we cannot get the server to turn on (stuck on an Amber light).

We tried minimizing the configuration, down to only CPU (no PCI bus, no HDD controller, no/minimal RAM). We also bought two new power supplies, which appear to make no difference. We have tried new and old power supplies in it, only one, several configurations. These problems started after a power outage.