I have MSOffice 2000 Small Business thay came as OEM on
my computer and since reformatting my hard drive, I can't
find the CD Key to reinstall it.
Then you have two choices: -
1) Contact the manufacturer of your system for a new key
or
2) Buy Office again.
Microsoft does not, will not and, indeed, cannot provide support for OEM
supplied software. All support - including replacement keys and media - is
the responsibility of the manufacturer/vendor. Please be aware that the only
version on retail sale now is 2003, which may not run on your system (it
requires Windows 2000 SP3 or later, XP or 2003).