I have a new PC with windows 8.1

I think, after trying all I can think of, is to re-install Office .

What are the pitfalls in doing an uninstall and installing again?

The biggest pitfall is that you might lose you Outlook .pst file, thus all your current Outlook data gets lost.

Check out http://www.chimpytech.com/backing-up-your-outlook-data/
for some advice on backing up your data, there are also some useful articles on moving, restoring, re-importing etc should you need to move / restore your .pst file.

You are also likely to lose any customisations you have made, so make sure you know how to re-create them again if necessary.

HTH

Neil

Hi,

Have you tried simply creating a new Outlook profile? Control Panel...Mail...Create New Outlook Profile.

If that doesn't work have you tried simply doing a Repair on Office instead of a complete reinstall? Control Panel...Programs and Features...Find Microsoft Office in the list...choose Repair.