Avast stopped when upgraded to windows 8.1

My avast pro stopped working when I upgraded to windows 8.1. I deleted and down loaded a one month version of pro. It will expire soon and I want to activate it with my license ID. What do I do to activate. It does not appear obvious

Assisi

avast FAQ section

http://www.avast.com/en-eu/faq.php?article=AVKB2#artTitle

http://www.avast.com/en-eu/faq.php?q=2014#searchForm

Thanks Pondus,

I worked out what I had to do and inserted the license file. Every thing is now fine.

assisi