So it\'s not a BIOS/IRQ matter, that\'s for sure.
Now, sinds we know that, remove all cards/devices from the board and powersupply try running at 133/166FSB.
If it works now, your powersupply can\'t handle the load.
If it doesn\'t I would suggest to redo the CPU-cooler, as it costs nothing to take it off and regrease it again.
See the trouble guide on this matter, all details for that are in there.
Let me know what the results are.