Outlook 2000 Reminders not popping up.

I have a user that no matter what he does, the appointments he sets do not come up and remind him. It used work on his Outlook, He had a problem with his PC, I had to reformat his drive and reinstall Office 2000. That’s when I noticed it didn’t work. We use roming profiles and Exchange 2000 on our network. What could be the issue?