/InstallVSTemplates (devenv.exe)
Registers project or item templates that are located in <Visual Studio installation path>\Common7\IDE\ProjectTemplates\ or <Visual Studio installation path>\Common7\IDE\ItemTemplates\ so that they can be accessed through the New Project and Add New Item dialog boxes.
devenv.exe /InstallVSTemplates
Remarks
When you run Visual Studio 2008 on Windows Vista, you must run devenv as an adminstrator in order to use the /Setup (devenv.exe) and /InstallVSTemplates (devenv.exe) switches. For more information, see User Rights and Visual Studio.