I am in the process of moving all of my projects from the old TFS2008 to the new TFS2010, and I am in need of removing the old projects so that none of my developers use them.
To do this, first backup your TFS Database as you should have a maintenance plan for it anyway to backup, but be sure to double check for that.
Next, run navigate to the IDE location in the Command Prompt:
· x86 Systems – Enter: cd "Program Files\Microsoft Visual Studio 9.0\Common7\IDE"
· x64 Systems – Enter: cd "Program Files (x86)\Microsoft Visual Studio 9.0\Common7\IDE"
· Type in: c:\Program Files (x86)\Microsoft Visual Studio 9.0\Common7\IDE>TFSDeleteProject.exe /server:[TFSServer] "[ProjectName]"
For example: c:\Program Files (x86)\Microsoft Visual Studio 9.0\Common7\IDE>TFSDeleteProject.exe /server:cstfs1 "Business Intelligence" 
· Next you will see this message:
Warning: Deleting a team project is an irrecoverable operation. All version control, work item tracking and Team Foundation build data will be destroyed from the system. The only way to recover this data is by restoring a stored backup of the databases. Are you sure you want to delete the team project and all of its data (Y/N)?
· Select Y if you are 100% sure you want to do this
Done!
