Yesterday, I replied to this request for help and due to my old age mis-spelled the device name. It is RestoreIT! Most computers of recent build already contain this device. RestoreIT! is the first item to activate at boot up. Consequently, any crashed system can be repaired in case boot up fails. As I write, I have no explanation for the Avast! 4.8 Home Email scanner error but, if you have RestoreIT! the problem can be fixed. All Windows hard drives are equipped with a "System Restore" but, RestoreIT! is different, exclusive unto itself. The principle is the same but much more efficient. With a crashed hard drive you cannot get to "System Restore" but the boot up will get to the stage containing a prompt to press the space bar to launch RestoreIT! just choose a date from the list where everything worked, the device requires about 20 minutes to do it's work. I'm an old geezer, not computer literate and I'll gladly vouch for RestoreIT! Best of luck in your repair work.
Gene