I bought a WD External Hard Drive some time ago specifically to back up periodically all my stuff, specially MSW Documents. At the beginning, whenever I saved a MSW Document it appeared a tiny screen at the button right side of my screen with the legend "This file has been back up in your External Hard Drive", which gave me peace of mind.
Nevertheless after a few weeks that system just stopped working. I called the Company and they explained me that what I have been enjoying was the "Free Trial Period", after which if I wanted to continue with the service I had to pay them a monthly fee.
Do you know a similar "Back up system" which I might download for free from any reliable website ?