Outlook 2007 Signatures and Stationary dialog box missing

I run into problem with Outlook 2007. When I selected Tools>Options>Mail Format>Signatures nothing happened. Restarted. Started in safe mode (holding down CTRL during start). No dialog box showed up.

The solution that helped was to run Microsoft Office Diagnostics available at Help>Office Diagnostics in Outlook.
Also at: Windows Start Menu\Programs\Microsoft Office\Microsoft Office Tools.