AVG Antivirus Update blocks network (Internet)

I work in a computer service. On Monday, July 22, 2013, the first calls from customers appeared that the network or the Internet had stopped working. When personally considering the situation, it was discovered that the AVG antivirus detects the tcpip.sys system file as a Trojan horse and blocks it. Therefore, the work of the Internet Protocol tcp \ ip v.4 is blocked.


The problem is noticed only on Windows XP.
Simply disabling or removing the antivirus does not solve the problem. Helps reinstall the protocol tcp \ ip.
I remind you that the same problem was with Avast antivirus in early December 2012.

At the moment, no messages on the Internet, on the site AVG not found.
Avastfix , developed specifically to solve Avast problems, will help.