Hello daswaff.

PROBLEM:
I noticed from your problem that the newest version of avast! IS blocks internet connection.

SOLUTION:
Try checking the firewall. It may have been blocked your internet connection by accident.

OR

Try looking at the network settings in the firewall (the ones with “HOME, WORK OR PUBLIC” sorry i forgot the names xD)
Put it on home (or depends)

Now see if your connection works. If it didn’t then there are much more answers to this problem that users or admins have.

Cheers