I got a red alert saying my update license was about to expire. What do I need to do to renew it? Free version I have.
Go to https://secure.avast.com/scripts/register.php?lang=ENG and register again for free.
The key is valid for 14 months only.
See the tutorial: http://www.avast.com/files/tutorials/insert_key.htm
Please take a look here: http://www.avast.com/eng/faq-invalid-license-number.html