So here’s the step-by-step that I promised a few days ago.

For this, I will be assuming you use Scrivener, but as I said before, this would be possible with any program that has an automatic backup option.

1. Downloads
   Install both of these programs on your computer.  Default settings on both are fine.
   Google Drive: https://tools.google.com/dlpage/drive (you’ll need a Google account, which you should have anyways because it’s free and awesome. 5GB of free storage)
   DropBox: http://db.tt/Nc4fWP7Q (signup is free, and signing up with this link helps me out by giving me extra storage for my account)
2. Backing Up Main Files
   In Scrivener, open up the project file for your book.  It should open up automatically when you start it.
   Click File, then Save As.  Navigate to the location of your newly installed Google Drive directory.  It should have installed itself in the favorites section if you’re using Windows 7.
   
3. Auto-Save
   While we’re in Scrivener, lets make sure that you have auto-save setup.  This will help us in case you’re not a paranoid freak about hitting CTRL + S like I am.
   In Scrivener, click on Tools, then Options.  Now make sure that the setting for Saving is at 2 seconds and the check box for “Automatically name” etc., etc. is checked.  Now, every time you stop typing for 2 seconds, Scrivener will save to your Google Drive, which is automatically backed up.
   
   
4. Auto-Backup to DropBox
   Now the fun part.  This is where we get the true redundancy that makes this so well protected.  While you’re in the Scrivener settings, click on Backup.
   This picture shows what all the settings should look like:
   
   The zip files option is really up to you, but it makes the files slightly smaller, which is nice.  Also, makes them a lot easier to download from DropBox should you need them because it is now one download instead of an entire directory.
   Also, I would leave “Retain backup files:” on Only 3.  There shouldn’t be a lot of need to keep more than 3, and since you only have 5 GB of storage on DropBox and could potentially have multiple Scrivener files as you work on multiple books (and use DropBox for other purposes as well), keeping three should be fine.
5. How to Use It
   Well, it is automated, so you don’t have to do anything different.  The one thing I would point out is that Scrivener won’t create the backup that does to DropBox unless you close the project (or close Scrivener), or manually save.  This is where my paranoia works to my advantage, so if you’re not the kind of person that hits CTRL+S a lot, maybe start doing that.

Well, that should do it.  If you have any problems or questions, throw them in the comments.  Oh, and stop worrying about your novel getting erased.  Your files are safe now!