Aside from S&D being somewhat dated, if you have the teatimer (real-time) function enabled we have seen that cause some issues with avast.

Not being able to uninstall (again presumably you get errors ?) is generally an indication of a corrupt installation.

  • Download the latest version of avast IS, 6.0.1125 http://files.avast.com/iavs5x/setup_ais.exe and save it to your HDD, somewhere you can find it again (if you didn’t save your last download). Use that when you reinstall.

  • Download the avast! Uninstall Utility, aswClear.exe find it here and save it to your HDD (it has uninstall tools for both 5.x and 6.0.x).

    1. Now uninstall avast! using add remove programs, if you can’t do that (as you have found) start from the next step, reboot.- 2. run the avast! Uninstall Utility from safe mode, first for 5.x if previously installed and then for 6.0, once complete reboot into normal mode.- 3. install the latest version, reboot.