|If it only happens when using Word, try this registry edit:|
hold down the windows key+R. This opens the 'Run' box. Type: 'Regedit' (without the apostrophes) then hit ok. This opens the Registry Editor.
In the registry editor, navigate to the following key:
HKEY_CURRENT_USER / Software / Microsoft / Office / 12.0 / Word
Then find the sub-key called 'Data'. Right click on that key, choose Rename and add a number to it i.e. 'Data1', then click off it so that the new name is saved. Try opening Word again and test the rightclick.