Silverlight Project Type not Supported in VS 2008 SP1 after reinstalling tools

This comproblem had me stumped for a while. The solution (simple as ever): open a command prompt to your c:\program files\microsoft visual studio 9.0\Common7\IDE and simply run:

devenv /setup

It may tell you that the operation could not be completed properly but it does mysteriously fix the problem - if anyone knows why I'd love to hear about it!

thanks - http://andrewgunn.blogspot.com/2008/03/silverlight-project-type-is-not.html