Ok, now I'm posting this before studying what you posted, jimac.

So I replaced the first 512 bytes of /dev/hda with a backup I found of it. Now I just get this when starting windows
Code:
MBR 123FA:
When I press anything on my keyboard other than "a" or "f", nothing happens. But when I press "a", it changes to
Code:
MBR 1234F:
And when I press "f" or press "f" after I've pressed "a" I just get an invalid system error (I can't remember what the exact error said) And it says right after the error to press any key. But before I have the chance to press anything, another error comes up telling me that it could not find "NTLDR".

So now I'm going to study your posts, jimac, and google around for this MBR 123FA: thing.