Avast Internet security update has blocked me from getting on the web??

I am running Win 7 Home 64 bit connected through a wireless AT&T “N” router.

My only Avast product is Avast internet security.

Avast told me there was a update I needed to install which I did then rebooted.

After installation I could not access the internet. The Win network and sharing center showed me with a strong connection to the router and it showed the router had no connection to the internet.

Win network troubleshooting said something about not identifying a DNS server.

Other computers on my network both hard wired and wireless are connected with no indication of problems.

I rebooted my router.

I did a recovery on my computer to before the Avast update and my internet connection was restored.

I installed the Avast update a second time and the same problem occurred.

This time the Win trouble shooter said it could not identify my problem.

I have done another recovery, everything is working again and am asking if others are having the problem.

I do not want to install this update again.

Thank you for any guidance.