During the weekend I upgraded one of my windows 8 pcs to the new 8.1.

This is not like a service pack. It looks more like going from xp to vista.  At the end looks the same.

The upgrade moves old data and programs into a new id. So some of the programs may work or may need to be reinstall again.

I have Magix Movie Edit Pro 2013. The program did worked under one of the ids and not under another one. Under the one that worked, I was still having problem asking me to re-activate some of the tools.

Solution that worked for me:

Uninstalled the Magix Movie Edit Pro 2013. Then reinstalled it and it remembered the license information from the registry. Then it worked fine.

If you have a mother board from ASUS, it may come up with an error message, not a big deal. On ASUS pcs, some applications may need to be uninstall before finishing upgrade

Windows 8 supports ends 2014.

Just an fyi for anyone who may have a similar problem.