[Jordan]

I realize this doesn't help very much, but when I bought this system and it had an older BIOS, I had to get an old P4 chip, flash it, then put the Pentium D in it. It supported all the previously released Pentium Ds (820, 830, etc.) but not the newly released 805 which ran at 533 FSB instead of 800. I guess it depends on the board.

You're right as far as Windows goes, sometimes it'll boot, sometimes it won't. I'd recommend doing a reinstall regardless, starting fresh is rarely a bad thing.