I bought my netbook (OS = XP) with version 4.8 installed. It was registered to the original owner. When that subscription expired, I downloaded version 5, and registered it to me. It wouldn’t work. The icon in system tray has an X next to it. I uninstalled and reinstalled. As soon as I rebooted after re-install, the X appeared.
I have a license key from the first version-5 installation, but I have never been able to get to the place where it should be entered.
Download the latest version of avast, 5.0.545 http://files.avast.com/iavs5x/setup_av_free.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, aswClear5.exe find it here and save it to your HDD (it has uninstall tools for both 4.8 and 5.0).
Now uninstall (using add remove programs, if you can’t do that start from the next step), reboot.- 2. run the avast! Uninstall Utility from safe mode, first for 4.8 if previously installed and then for 5.0, once complete reboot into normal mode.- 3. install the latest version, reboot.