Unable to access AVG UI menus

I successfully updated AVG (the FREE version) yesterday and then used the UI to disable “HTTPS scanning” – this fixed a problem I had been having with my browsers for the last week: downloads would not complete. 
 
I then started a full scan.  I later found I couldn’t stop the scan or find out how far it had got.  In fact I can’t access any of the menus any more: the menu options (Device Settings, etc) don’t seem to help.  And opening Antivirus Free just displays AVG Antivirus FreeYour Internet Security Trial has expired.   Well, I don’t think I have intentionally taken part in a trial and as I said, I can’t access the menus any more.  What do I need to do to fix this problem?

Thanks for your reply - I will do as you suggest.  But you may be interested to hear that the menu items 'came back' this morning after the PC had been asleep overnight.  But only one time - it is back to the problem scenario now.

Andy,
Sorry to hear that. Please uninstall and reinstall AVG Free Antivirus as suggested in previous post and check if it works.
Thank you.

Thanks for your reply - I will do as you suggest.  But you may be interested to hear that the menu items 'came back' this morning after the PC had been asleep overnight.  But only one time - it is back to the problem scenario now.