No luck. I uninstalled Avast through add/remove programs.
Then I booted into safe mode and ran both the Avira and Avast uninstaller tools.
Booted back up in normal mode, re-installed Avast. Rebooted
Stuck on the loading screen.
Exactly the same symptoms as before.
Restart, "use last known good configuration," then boots back up to the desktop, but Avast complains that the service is disabled.
What could this be? I find it odd that Avast works fine on my XP machine, but not my Father's. Both have fresh installs of XP SP3 after a complete format from nearly the same time (only a few days apart.)