Office 97 very slow in Windows 2000

We are running Windows 2000 Professional Clients, logging onto an NT4 domain and using Office 97. Most of our users are experiencing problems starting Office apps. The application takes a very long time to start, sometimes up to 5 or 10 minutes. Task manager shows the task is running. We are currently getting users to log off and log back on again and this fixes it temporarily. Some users need to log off several times a day. We don’t have this issue with any other software running on ourPC’s.