8RDA+ won't POST

I've got an 8RDA+ system that was running fine early today. (It is not
overclocked, but I'm thinking overclockers may have some insights too,
hence the cross post.)

It was left on while people left the room. When they came back a few
hours later it was dead. Now it won't even POST.

History: ~3 weeks ago it started giving a message at boot time saying
the CPU had changed. (It hadn't)
I swapped in a new CMOS Battery and after a lot of other Windows
related issues had the machine running fine again, except that it
would complain that the 80 conductor 2nd-ary IDE Cable was not
connected. (it was)
After a while longer, it failed to boot because it didn't detect the
floppy (which was still connected). I went into the BIOS and told it
to ignore that error. It booted fine and continued working.

Now it's dead. A few times I was able to get the power and fans to
come on but the system would not even get to the BIOS screen. I
checked the PS with a volt meter and got proper voltages on the
peripheral connectors (+5v, +12v) The LED error codes would stop at a
different value each time it froze: 00, FF, C1, CF, 0d. It was very
random. I would sometime get long beeps. Then I started getting hi-
lo-hi-lo alternating beeps.

I disconnected ALL the IDE cables and their power supplies and even
the MoBo from the PS. Then I reconnected them all and now I don't
even get power or fans. I can see the NIC lights (yellow and green)
come on, and I can see the LED briefly flash FF (0.5sec).

I'm starting to think the BIOS Chip went south. Any other
suggestions?

This machine has been a trooper and I'd hate to see it go.

I'd appreciate any pointers.

Thanks.

Glen