Hi fiddlerdan. Welcome to the forums.

Windows XP spk 2 or 3 ?
What Avast; Free, Pro, IS or Premier ?
Any other security program active ?

if it is a paid version, you can have the lincense send to you again:
https://www.avast.com/resend-license-paid.php

Repair Avast:

Start > Control panel > Add & Remove programs > select avast! and click " Change/Remove ". Highlight " Repair " and then Continue. When Avast finnishes the repair, reboot the system.