If you want to activate Avast Antivirus then you can go with these methods: You can use your Avast account to activate your antivirus software. First you need to login and go to Subscriptions section of your Avast account, and click Activate button which will be just next to the appropriate subscription. To finish the activation process, you have to follow all the instructions. While purchasing a retail version of Avast Antivirus, you will receive an activation code. You have to open the setting of Avast Antivirus and then go to Subscriptions section then tap on Enter Activation Code. Finally Enter the code and tap on Activate button.