Is the registration key the same thing as the license key? & which one do I need to renew my subscription?
They are pretty much one and the same thing, it would depend on what avast version you are using. The Home versions sees it more commonly referred to as the registration key. In the case of the Pro version it is commonly called the License but why ever you have the resultant key gets entered in the same place. See image and you will see both are referred to in the about avast pop-up.
So are you using the Home or Pro version of avast ?
Ok. I’m using the home edition & I accidentally deleted the e-mail I got when I registered. But when I click on “About Avast” it shows a registration key number. Is that what I need to renew?
It not only shows you the key number (only part of it) in the display but it also tells you when it will expire, e.g. Updates expiration. That is what you need to renew.
You can re-register - Complete the avast! 4 Home Registration form and you will receive an email from register @ avast.com (without the spaces) with your registration key.
Also see Insert Registration Key - Video.