If no items are listed in:
IDE | Tools | Options | Environment | Keyboard
You can restore keyboard schemes with one of the commands:
devenv.exe /installvstemplates devenv.exe /resetuserdata
Also, see the following for a possible solution:
http://groups.google.com/group/microsoft.public.vsnet.ide/browse_frm/thread/93a7c52c02347d77/f1d972c28743391a