French Chemist-- Usually the quickest and simplest way to solve your problem of installing AVG antivirus is to uninstall the program completely from your computer and reinstalling.http://www.grisoft.com/doc/7/lng/us/tpl/tpl01
288: How to uninstall AVG?
Click on Start > All Programs > AVG 7.5 > Uninstall AVG Anti-virus for Windows.
If you experience any problems with the uninstallation procedure, please follow the steps below:
Download the latest installation file of AVG from Downloads-Programs.
After downloading, run this file and choose the Uninstall Product option in the Select Setup Type dialog.
Finish the uninstall process.