Here are the steps to get your items back. Navigate to C:\Users\
\AppData\Local\Microsoft\VisualStudio\9.0 (on Vista or Longhorn) or “C:\Documents and Settings\\Local Settings\Application Data\Microsoft\VisualStudio\9.0” (older Windows versions) from a command prompt or in explorer (you may need to configure explorer to show hidden folders: Tools -> Folder Options -> View -> check Show hidden files and folders). Here, just delete these files:
· toolbox.tbd
· toolboxIndex.tbd
· toolbox_reset.tbd
· toolboxIndex_reset.tbd
Then restart VS 2008 and the toolbox should look normal again. Same steps apply to VS 2005 (just replace 8.0 with 9.0 in the path)
http://blogs.msdn.com/oanapl/archive/2008/06/08/visual-studio-2008-missing-items-from-toolbox.aspx
