You have to use the tfsdeleteproject
command from a visual studio command prompt. Here is the syntax:
tfsdeleteproject /server:your_tfs_server project_name
Note that when deleting TFS projects, you must be the project creator to delete the TFS project. If you weren’t the creator of the project, then you have to be a member of the “Site Collection Administrators” group on share point portal for the project, and you must be a member of the “Team Foundation Administrators” TFS group.
EDIT
For workspace deletes, use the following instructions:
Use the command line utility tf
.
You can get a list of all workspaces by bringing up a Visual Studio Command Prompt and using the following command:
c:\>tf workspaces /owner:*
You should see your problem workspace in the list as well as it's owner.
You can delete the workspace with the following command (substitute BUILDSERVER, WORKSPACENAME and OWNERNAME accordingly):
C:\>tf workspace /delete /server:BUILDSERVER WORKSPACENAME;OWNERNAME
Refer here for more info.
So you could delete the workspace and recreate it, then reimport your projects.