I'd try this. Uninstall Outlook. Download and run CCleaner. Reinstall Outlook.
Get the Slim version of CCleaner at
http://www.ccleaner.com/download/builds It's the same as the standard version except that it's English only and has no Yahoo! toolbar bundled with it. For some info on using CCleaner, see
http://www.jahewi.nl/ccleaner/folders/folders.html and
http://www.jahewi.nl/ccleaner/issues/issues.html . This info is a little out-of-date but is still pertinent. The CCleaner menu button formerly called "Issues" is now called "Registry". So, replace "Issues" with "Registry" when reading the content on second link above.