Outlook works by referring to a data file known as your Profile. Sometimes this can become corrupt and needs to be replaced or Outlook suffers other issues where creating a new profile would be the quickest and easiest fix.
The attached file walks you through the process of creating a new profile and replacing your old one.
WARNING!
ONLY USE THIS SOLUTION IF REQUESTED TO BY A MEMBER OF THE IT SUPPORT STAFF - NORMALLY WE WILL DO THIS FOR YOU BUT IN SOME INSTANCES YOU MAY HAVE TO ATTEMPT THIS YOURSELF!