You can disable AVG temporarily on your computer and check if you are able to update.
To disable AVG temporarily, please right click on the AVG icon present at the bottom right corner of your desktop(System Tray) and use slider to "Disable Protection".
I will check this for you.
Please let me know the version of AVG installed on your computer. To check the version, open AVG Internet Security, click on "Menu->About".
Do you get any error message from AVG when you try to update AVG?
If yes, please share the screenshot http://avgclick.me/getscreenshot of the error message to assist further.
You can disable AVG temporarily on your computer and check if you are able to update.
To disable AVG temporarily, please right click on the AVG icon present at the bottom right corner of your desktop(System Tray) and use slider to "Disable Protection".