Rodus

When you install a CPU upgrade you have to pull the old card, press the reset button, THEN install the new CPU. I had that problem with my G4 1000 upgrade. My 7500 wouldn't boot until I had removed the upgrade, pressed the reset button, and then reinstalled it.

Dog Cow,

Find the reset button on the motherboard and try pressing it with the CPU out and then reinstall it and try starting up again.