Sorry to bring this up from the dead, but this is still a problem. I tried running fixboot and then fixmbr, and nothing at all has changed. When I ran fimbr, however, it told me something like "this machine has an uncommon or non-standard mbr" and warned me that it would make my disk unusable. I ran it anyway.

But it still happens. It still boots up past the "Verifying DMI pool data" and then I just see a black screen.

I've done everything I can see to do within the BIOS to try to force it to the correct drive, but I don't think that's the problem anyway. It's just very strange that if this happens, I just need to press the restart button and it boots up to the old "this computer didn't shut down normally, what would you like to do," then I can select to boot normally and it works fine...until the next time the computer is turned off normally and then turned on again.

Any more ideas? The BIOS is new, the settings in it look fine, I've run fixboot/mbr, and I can't think of what else could be going on...