RE: Avast killed my internet connections
At first, I need to mention that Avast is not developed nor distributed by AVG Technologies. You should probably seek help in the Avast forum.
The cause of the issue could be that Avast removed an infection which acted as network filter and the infected driver was not replaced with a clean variant of the driver. But this is mere speculation. I think Avast customer care specialists will troubleshoot the situation with you.
It is also a good idea to check your proxy settings, DNS configuration and uninstall other network filtering software as mentioned by R. Proffitt.
Please refrain resurrecting old threads in forums. This thread seems to be almost 2 years old. It is likely that the thread, though it has a very general name, is not describing exactly your issue. From the troubleshooting point of view, it is better to describe individual issues in separated threads. The forum is easier to read for other visitors.
Please let us know if you need some assistance with AVG in future.