I started a post about what antivirus are you using and got most AVAST reply. Then where did you buy these program? From the official website or other stores?
yep, you can...you can try the trial also, then if you like it, just pay for a subscription and you will be sent a code to type into the software to make it the full version..
Avast has a free option that you can choose to use. It does everything that you need without having to pay for a paid version. Just google Avast and you will be able to download it for free.
i use kasperksy but avast you can easily buy by going to the original website of the company and but there the official paid version.