Hmmm, unsure now,
Normal way to reset the bios, is move the jumper to pins 2-3 turn the machine on for a few secs, turn off. move the jumper back and your'e done. Not convinced now thats what it is.
When you said you put the MB in you said you put all the pci cards in etc. Now, what if one of those cards caused your first MB to die in the first place. Changing the chip didn't help much. Changing the MB put you back where you were before. Changing the power supply didn't help either.
Ergo, all thats left is the PCI/AGP cards and drives.
Rip it all out and start over.