I lost a whole day wandering around your site. Why the hell isn’t there any email address to contact Avast?! I did not find how to extend the period of operation of Avast free antivirus. Where and how to get a license key?
There is no license key as such (that you have to obtain). So can you explain in a little more detail, e.g. Why do you need to do this. ?
Ordinarily you should get a notification a couple of weeks before the end of the year (the default period after installation), renewal should just be a case of clicking renew.
You might try Right clicking on the Avast Tray icon and select Registration, see attached image, click to expand.
EDIT:
DON’T click the UPGRADE Now button as that will result in getting a Paid version of Avast. Click the down arrow and it will show your Registration.