Formatting A Computer--- backup Avast?

So, I’m currently trying to back up all of my friend’s important files on her computer so she can format it. However, she informed me that she has the PAID (I’m guessing Pro) version of Avast.

What is the best way I can back up Avast so she’ll be able to use it again after the format?

you only need the license key, that she got in a mail ( avast.click ) the program you just download again

avast! 5.x: Inserting the license file into avast! Internet Security
http://support.avast.com/index.php?languageid=1&group=eng&_m=knowledgebase&_a=viewarticle&kbarticleid=476

avast! 5.x: Inserting the license file into avast! Pro Antivirus
http://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=475

Don’t backup the whole program, it’s best to save the license file and reinstall avast after the reformat.

Is the license file still saved somewhere on her computer? Or would I have to get them to resent the license key.

Did she save the file? Yes, found the license.avastlic file. No, try to find it attached to an email. Can’t find? Ask for a resent with the same email address as she bought it.