I had this same problem on one of my computers at home.  Repairing and reinstalling Office 2007 did not fix it.  I did figure out that changing the theme back to one of the default themes did correct the issue.  Just select one of the default windows themes and presto, it is fixed.  Definitely a lot easier thatn recreating the profile.  Just modify your profile to the background you had before with office 2007 installed.