hello, im trying to install avast, but how do i get the lisence to go into the installing program?
What version are you going to install free/pro/ais version (pro/ais are paid versions and you need to purchase a license) ?
Before installing avast, download and save the installation file to your hard disk, uninstall existing AV, reboot and install avast.
G’day and welcome to Avast their are two ways to get a free license IF you’re using the Avast Free version only see link for information easy step by step instruction https://support.avast.com/index.php?languageid=1&group=eng&_m=knowledgebase&_a=viewarticle&kbarticleid=1073
im trying to install the avast pro, i have the lisence key. mut how do i use it? on windows vista
Once you have Avast Pro installed then you should be able to double click the license file that was sent to your email when you purchased it and it will install automatically.
i have double clicket the lisence file but it wont start, when i click the file it just start google ghrome
Try and fellow this video tutorial it does the same way in the Pro version
Inserting the license key into avast!
https://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=1037&nav=0,616,617
OR
Activation of avast! using the license file
https://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=1183&nav=0,616,617
when i try to do this it just opens google chrome. it asks what program i want the file to be opened in.
I don’t used google chrome just sit tight and somebody will come and help you okay 
The way I always insert my license is to save the license file to the desktop and double click it from there
I will ask the blindingly obvious (willing to risk looking daft by asking), have you actually downloaded and installed avast! Pro ?
If so what file have you saved and are double clicking on (it should be license.avastlic) to insert your license ?