Postup:

1. Run the AVG Free Edition 7.5 Setup program
2. Click "Next >" on the AVG "Welcome!" screen
3. Click "Accept" on the "License Agreement on Use of an AVG Free Edition" screen
4. Select "Repair installation" on the "Select Setup Type" screen and click "Next >"
5. Select "Restart the computer now" (pre-selected by the program automatically) and click "OK" on the "Installation Complete!" screen to restart your computer and complete the installation

http://free.grisoft.com/doc/3/lng/us/tpl/v5

edit: mně ten postup nefunguje, takže jsem AVGFree 7.1 odinstaloval a po restartu nainstaloval tuhle verzi: http://free.grisoft.com/softw/70free/setup/avg75fre e_428a818.exe - šlape OK.