Premier trial expired, can't enter 5 units license

After the trial version of Premium Security expired, I want to use my 5 units license. But the software only offers one possibility: BUY.

Tried to uninstall, in order to make a fresh install and have a chance to enter the license (worked for 2 computers before the one I have problems with today), but the Avast’s uninstall instructions don’t fit into what my computer shows (Win10 Swedish) - only two possibilities here, Repair and Change.

Can someone explain?

Clean Install of Avast:
https://goo.gl/4Ptzkf
If you need additional help with the Clean Install, watch this:
https://youtu.be/p-h3myRD51A