Trouble browsing win2k domain

I have a client that is have problems browing our domain. She is using
a Win2k box for software testing and when she tries to browse the
domain, but only the first time after a restart, there is an error
stating that she is trying to browse an unknown domain. So for what she
is doing, she opens Windows Explorer types \\servername and when she
hits enter windows adds :n after the server name. Then the process
stops responding and hangs. Once you end the task and try it again its
fine, it doesn't happen again until you restart. I'm completely stuck
on this. If anyone has any help that would be great.

Thanks
Techguy83