in that case you have a few options (assuming you use IE here)
either disable the toolbar, by selecting tools manage add ons and then "enable or disable add ons" and find the avg add on and disable it. (this will only disable it, not remove it)
or uninstall AVG totally and then reinstall it taking a tick out of the "install AVG toolbar" option during one of the steps.
Sorry I said a few options, the last one is the worst, which is just hide it. click the view menu, then toolbars and click on the AVG toolbar and it will turn it of, this is only hiding it from view though.