I have noticed that we are having difficulties diagnosing network problems. Some Suggestions..

Check Cabling, and check for a light on the Hub.

Not being able to log on NT, this is
often caused by incorrect workstation settings.

Check to make sure they are using NT SP 4 or SP 5 only
Try logging on as another workstation number.If this works go into Start- Programs-Administrative Tools-User Manager. Then delete the original workstation number.Highlight the current workstation number, hit F8 to copy it to a new user. Name the new user the original workstation number.

Problems with Nt logging onto Novell.

Click My Computer-Control Panel-CSNW.
Make sure Prefered Server name is correct. Also make sure Run Login Script is checked.