I have just had this same issue today, two issues here:
1. I don't know how to (or want to) start doing this (pk) ...
>>> Hi, thanks for your bug report.
>>> There's probably a bug in Free -> Pro upgrade. Can you please install Free, upgrade to Pro (don't reboot) and then:
>>> 1. run regedit.exe (go to HKEY_LOCAL_MACHINE\System)
>>> 2. File -> Export (Save As Win9x/NT) and save the file
>>> 3. Please compress this file (zip/rar/7z) and upload the file on our ftp? (in Explorer, open
ftp://ftp.avast.com and Drag & Drop the >>> file there.
>>> 4. You can also run
http://public.avast.com/supp/util/avastsupport.exe tool to upload setup log
>>> 5. Now you can uninstall avast (or remove that entry from UpperClass)
>>> Thanks a lot!
You REALLY expect normal (non techy) people to actually do this to solve a (clearly) well known Avast software problem. Why haven't Avast sorted this???
2. I called the "customer support" for help line who logged in, simply brought up the Reliability Monitor in Control Panel, said "look your PC is in a terrible state" (which it isn't) and then wanted to SELL me the services of their engineer to clear this up. Unbelievable - Avast same sales tactics as those dodgy tradesmen you get knocking at the door, very poor.