Q: I have updated avast! HOME to version 4.1. Now I can´t start avast and It asks me to buy it. Why is this?

A: There was a little bug in the first release of avast! build 4.1.259, when the license keys generated in January 2003 were wrongly identified as invalid. The easiest solution of this problem is to register again on our website. You will recieve a new activation key via e-mail. Start avast!, ignore the first window asking to buy avast! and insert the new license key.