Going from Outlook 2000 to 2003

Everything seems to be set up fine.
I have all my messages in the inbox and names in contacts but when I go to create an e-mail and start type an address the autofill does not work.

If I click :to I get a list of all the e-mail addresses but that's it. No autofill.

On a side note... What's the difference between contacts and address book? Do I need an address book if I have contacts?

And one more for the weird file...
I'm working on trying to figure this out on a test machine. Autofill is working on it so I was trying to figure out where that info was coming from. I deleted ALL contacts, ALL e-mail new and old and when I go to create an e-mail and start typing in an address... It STILL does autofill. WHERE is that info coming from? I have deleted everything that I can see?

THANKS!!