Avast Help:

Download and install old version of Avast, either of the first 2 editions of Avast 7.

http://www.filehippo.com

Before you can install an old version of Avast, you may need to set the date back to 2010, 2011, or  2012.  30 year license does NOT work with latest version.

Right click Avast icon on Windows task bar then left click registration info

If your Avast antivirus is not already registered or your registration has expired then

scroll down to manually enter license key.

copy and paste key below into Avast.

W6754380R9978A0910-4TZ59467

Beware your firewall will complain Avast has changed.

Accept the changes to Avast reported by the firewall.

If your Avast antivirus is already registered or your registration 
has NOT expired yet then change the Windows date 2 years into the future.
Restart PC

Right click Avast icon on Windows task bar then left click registration info

scroll down to manually enter 30 year license key.

copy and paste key below into Avast.

W6754380R9978A0910-4TZ59467

Change back the date to the current date.

Beware your firewall will complain Avast has changed.

Accept the changes to Avast reported by the firewall.