Equation editor not embedded

Urgent!
Does anybody know how to make Equation editor embedded into the word document?
I have windows 2000 professional, I have uninstalled and reinstalled MS office 2000 three times, the Equation Editor still cannot be embedded in the word.I haverun the repair through add/remove program in control panel, no luck.
It was working fine with windows 98. anyone can help please!
Thanks