This may be trivial. I am trying the following in order to delete a user from a TFS Project that I created:

C:\Program Files\Microsoft Visual Studio 2005 Team Foundation Server\Tools>tfssecurity /server:ServerName /g- [TFS Project Name]\Project Administrators n:DomainName\username

I keep on getting :

Error: The identity cannot be resolved.

Also, can someone give me the syntax of deleting a user from the licensed user list for TFS workgroup.

Well eventually, the actual syntax turned out to have quotes etc. It was:

C:\Program Files\Microsoft Visual Studio 2005 Team Foundation Server\Tools>

TFSSecurity /server:http://servername:8080 /g- "Team Foundation Licensed Users" "Domain\user name"

And after doing this, I could reinstall TFS.

The syntax's hint is also in this post:

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=639233&SiteID=1