When trying to install the latest Internet Security, it fails at about 95% of the way to completion. Now when trying to reinstall my Internet Security 2015 it won’t run or install either. I don’t know if this makes any difference or not, but I am running Windows 10 Home Edition 64-bit as my OS. Right now I appear to be unprotected except for what Windows Defender can do for me which I suspect is little to nothing. HELP! :o
Perform a clean installation of the latest avast version.
- Download the avast version you want : https://forum.avast.com/index.php?topic=182468.0
- Disconnect from the net (physically)
- Remove avast through control panel
- Reboot
- Run avastclear : https://www.avast.com/uninstall-utility
- Install avast
- Reboot 2 times (to make sure all changes take effect)
- Connect to the net
- Reboot
Eddy, thanks for the info, however it didn’t work in my case. I finally had to breakdown and purchase a 30 day Tech Support package. It took a couple days, but they got my system working. As far as I could tell it appears that a malware got into my system. Funny thing though is it only seemed to affect me. My Wife’s account was, as far as I could tell, totally unaffected. Watching what the tools that Tech Support people used was very fascinating. I know I can say kudos to them for getting my system back up and running normally. I guess that makes it worth the $119.99 it cost me for the package. 
Waste of money.
Help here is free and better.