Missing the updates (brushes, plugins) after reinstalling GIMP
If the updates were installed in the GIMP folder then you’ve lost them for good and all. The missing cannot be undone. But if they were installed in the user folder, probably everything still remains in the other users’ folders. So you should simply drag the folder «.gimp-2.6» to your profile :\Documents and Settings\username\.gimp-2.6\
This folder also stores tools configuration, shortcuts and position of windows.