License file/ License key

I love Avast, but for some reason when I installed it on my new laptop, it keeps “expiring”. I never had this happen before. I registered again and was sent a license key, which from what I understand is supposed to be entered under maintenance/ registration, but when I go into maintenance, all I see is a subscription tab where it asks for a “license file”, which I don’t know anything about. Tried to contact Avast, but no reply. I don’t want to go back to AVG! Any ideas? Thanks in advance.

Sorry if this appears twice, there was some captcha confusion!

registered how?

Registering avast! Free Antivirus
https://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=1073

Thanks for the quick response. I’m not too sharp when it comes to computers, but I’m pretty sure I did online registration. Also, I think I have a different version, mine doesn’t look like what is pictured in that link. Under “current version” it shows 8.0.1455