BOAC I subscribe to a web site that helps out with Windows etc. and they recently sent this out:
AVG antivirus is causing patching headaches
"As if we didn't have enough patching emergencies to deal with this week, a recent update of AVG's antivirus software knocked out some people's Internet connection. AVG's support page indicates that after upgrading to AVG version 8.0.196, your network link may fail.
If rebooting your PC doesn't fix the problem, follow the instructions on AVG's support page to download the fixfiles.zip file to your computer. Double-click the .zip file to open it, and then double-click fixfiles.exe in the resulting folder to run the utility.
If the glitch persists, the company recommends that you run a repair installation of your AVG app. If reinstalling your antivirus software doesn't get you back online, AVG advises that you contact the company's support desk for further instructions.
I became aware of the AVG update glitch when the program began to interfere with the collection and distribution of e-mail on my Small Business Server 2003 test system."
May be of help, maybe not?