Outlook2K/Default User

Outlook2K/Win95 Users/NT Server/MS Exch 5.5:Recently when a couple of the users have switched to a different workstation (other that the one that they normally use),they are unable to access their email.They can open MS Outlook, but not access theiremail. I have tried to go into the Mail properties from the individual workstations and changing the profiles in the “Ctrl Panel>Mail icon”,no luck.The users have no problems accessing the network or network resources. Is there something that I am overlooking?