Lost address book in Oultook 2000

I have a user using Outlook 2000, and all of her messages and contacts have been lost in the system and I haven’t been able to find them. She is working on an NT workstation 4.0 machine and when you go into her account, nothing is listed. Are contacts and messages stored someplace other than a .pab file? I found a mailbox.pst, but have not been able to import or copy it into her profile. All data is saved to the local hdd, and we are not using Exchange server. I’m running out of things to try, anyone got any suggestions???