activating Office Assistant

Hi, I'm running Office 97, version 8.something. When I
try to activate the Office Assistant, to set up email
rules, I key the "Tools" button, and find that the Office
Assistant tag is greyed out, thus unaccessable.

How do I activate said creature?

Sorry to be a pain, put could someone respond to my email
account, as I seldom get on the Web. Many thanks, Paul