The Repair should have given an indication it had completed, did it ?
Whilst not normally required I would always recommend a restart after the Repair.
If you did the above then a clean reinstall would be the next option:
See the link given by Michael529 in Reply #2 and follow those instructions.
Before you start anything get your tools together so you have all you need first, download avastclear.exe and save it then download your Avast Antivirus Program, links here (use the off-line installation file, rather than the online version)
https://forum.avast.com/index.php?topic=229461.0.
Now Uninstall your version of avast, reboot.
Using the files you downloaded and saved:
Run the avastclear.exe file, reboot.
Now reinstall your program, reboot.