If Outlook won't open, try opening it in safe mode, which disables add-ins.
1. Right-click the Start button, and click Run.
2. Type Outlook.exe /safe, and click OK.
Tip: If Windows can't find Outlook.exe /safe, try using the full path to Outlook (for example C:\Program Files\Microsoft Office\OfficeXX, where XX is your version number).
More on starting Outlook in safe mode and disabling add-ins.
