SyncToy

SyncToy is a remarkably useful free utility from Microsoft. It assists in the process of backing up files from one volume/drive to another. Simple, easy to use settings allow users to select a source and destination folder and choose whether the files are mirrored (altered on volume B when A is changed, and vice versa) or echoed (changed in one direction only). After your initial (and possibly quite lengthy) backup using SyncToy, the program subsequently only transfers files that have been altered since the last backup, which speeds matters up considerably. Very useful if you want to create multiple backups on your files (you really should!)