I use three different methods to back up ACT. The first is ACT’s backup feature (file | backup) and the second is file | save copy as. The first method saves ACT as a zip file and the second creates a duplicate database. The third way I backup ACT and all the contents of my computer is Carbonite.
Carbonite is a remote backup service that costs just $49.95 a year and backs up all the files on your computer automatically. The reality is that you don’t even need to backup ACT at all when you use Carbonite.