How to disable Avast opening Chrome

My default browser is Firefox, yet when I boot up my computer Chome opens without prompt to some Avast page. How do I stop this short of uninstalling Chrome? I could find no options in msconfig, browser settings or Avast Settings.
Thanks

does this help
http://productforums.google.com/forum/m/#!topic/chrome/g0VKA4wjo4M
http://productforums.google.com/forum/m/#!topic/chrome/fppkeAKNntw

Check out my possible solution in another thread: http://forum.avast.com/index.php?topic=140849.0 it’s post #8 in that link.

By the way, Pondus, neither Google Groups conversation has the correct answer, which is that it is Avast! itself that is starting the Chrome, not Chrome.

Thanks, just got rid of Chrome… Guess I should get rid of Avast instead.