change of operating system

Hello, i am currently using Avast Internet Security with windows xp. i intend to format hd and do a clean install of Windows 7. What do I need to do to make sure I can continue to use AIS with Windows 7 (without loosing my current licence etc). Would appreciate feedback on this

You can download and install from here:http://files.avast.com/iavs9x/avast_internet_security_setup_offline.exe
Recover Avast license again:https://www.avast.com/resend-license-paid.php

Thank you for prompt reply

Make sure your hardware can handle Windows 7 (decently).