Immediately I could no longer send emails, I could recieve but not send. I would get SSL errors. I also found out that with Avast installed, if I tried to access my router's admin webstyle page, it would crash the router completely forcing me to hard boot it in order to get my network back online.
I didn't bother to troubleshoot Avast itself as I had an alternative AV at the ready that didn't cause those issues.
Now, last night, my brother who lives 2000 miles from me installed Avast AV. Immediately he could not send emails, getting a totally different error then I got (his ISP does not require SSL to access the SMTP server). Removing Avast solved this issue.
Is there some way to make Avast play nice with my router and outlook express? Like I said, I haven't really bothered to troubleshoot beyond a quick google of my issue. Maybe someone has a ready explanation here as it seems like a great free AV package otherwise.