Clearing the cache may rid of credentials being cached:
C:\Documents and Settings\<you>\Local Settings\Application Data\Microsoft\Team Foundation\1.0\Cache
When you connect to TFS from the standard Visual Studio Team Explorer it remembers the credentials used to connect to the server. If, for whatever reason, you find that these credentials are no longer what you want to use you will have to change the credentials
I found from this blog that
"it's possible if you physically log in to the Team Foundation Server using a different set of credentials. Those credentials are cached deep in the bowels of Windows, and retrieved automatically the next time you contact the server. "
"To clear the credential cache, try Start, Run, then type
And press enter. On the resulting dialog, click the advanced tab, and click Manage Passwords. Remove all cached credentials from this list.
"With this in mind, if you must log in to the Team Foundation Server, try to do so under your own credentials. It'll cause less problems later. "
The Microsoft support page for this functionality, for Windows XP, describes:
"Stored User Names and Passwords is a mechanism that dynamically and manually creates credential sets (a user name and password) for resources. This functionality is available from the graphical user interface (GUI) and from the command line. The types of credentials that you can manage with Stored User Names and Passwords are:
|•||User names and passwords|
|•||X.509 certificates (smart cards)|
I have some users in Windows 2000 so will be posting the solution for them here.