I have recently changed my internet provider and email address but since doing so I have been unable to update my avast subscription. What should I do
Usually, it’s just that the registration email gets stuck in the spam folder.
Use your webmail access to see if it’s stuck in the spam folder (or your email client) and see if it’s in there.
If not, try the online registration method.
http://www.avast.com/registration-free-antivirus.php (I believe this is the Offline registration form)
Or, check this thread: http://forum.avast.com/index.php?topic=54734.0
Or, go to the re-send license form: http://www.avast.com/resend-license.v2.php