Is it likely that conflicts contributed to the drive crash?
Did you uninstall Norton before installing AVG? These two could possibly conflict with each other. Make sure that Norton is 100% removed from your system, or it will likely crash again.
Make sure that Norton is 100% removed from your system.
Indeed. That may however require downloading the Norton Removal Tool, as the uninstallation of Symantec's Norton software products is bound to leave many registry entries and files on the system.