Help needed: Asus P4P800-SE & Celeron D 345 - won't boot

Summary of my computer:

Asus P4P800-SE motherboard BIOS Version 1011
OCZ 2x512MB PC3200 Dual Channel DDR-RAM
ATI Radeon 9550 with 256MB VRAM
LG DVD+/-RW drive
Maxtor 250GB hard disk with 16MB cache

Right now I am using a Pentium M 1.4GHz overclocked to 1.82GHz (using Asus CT-479).

When I swap the processor with a Celeron D 345 3.06GHz, the system won't boot. Resetting the CMOS didn't help.

The processor works in a MachSpeed Matrix P4M800 motherboard. So the processor is good.

The Asus website says that the processor has been supported since BIOS 1007.

Has anybody come across a similar situation? I would appreciate any possible solutions.

I used the same 400W power supply with both mobos... didn't work... I even pulled out all non-essential drives and cards, and swapped the Radeon 9550 with a Rage 128.

I am using PC3200 DDR400 RAM. That's 200MHz dual-pumped (400MHz effective / DDR400 ... duh).

If I use the Pentium M 1.4GHz at its native speed, the memory runs at 133MHz dual-pumped (266MHz effective / DDR266). The computer is stable at this setting.

When I overclock the processor by 30%, the memory is running at 133MHz + 30% = 172.9MHz ~ 173MHz dual-pumped (346MHz effective / DDR346).

The system is stable at 5% OC (DDR280), 10% OC (DDR293) and 20% OC (DDR319) as well.

So, the memory is stable at DDR266, DDR280, DDR293, DDR319 and DDR400.

The Celeron D has 533MHz FSB. If I set the FSBRAM ratio to 3:4, the memory should run at DDR400, which is what it was made for.

By the way, I used the same sticks of RAM in the MachSpeed motherboard. So I doubt that the RAM is defective/questionable. I doubt if the Asus motherboard supports an FSBRAM ratio of 3:5 (Why isn't the memory running at DDR333 when the processor is running at native speed? I can't even change that in the BIOS.)

[ I did a lot of maths above. Give me a nasty reminder / rude awakening if I made any mistakes ]