Install key problems

[Fabian]

I have a machine that lost it's boot drive. I replaced
the drive and when trying to re-install Office XP pro, I
get a "product key not valid". This is the key from the
back of the CD case and was installed on the same machine
before the crash. I have tried upper-case, lowercase,
numbers from the keypad, numbers above the letters.
Nothing works. I am at a loss. Any help would be
appreciated