Paragon Backup & Recovery Free Edition is a powerful disc-imaging and recovery solution.

It is the only one that can do differential backups; create a bootable USB/flash drive and execute automatic data exclusion option.

It also supports all existing backup techniques, performs disc imaging to any backup destination and supports Windows 7.

"Take complete control of your PC’s safety. Based on solid commercial backup and recovery software from Paragon, the new Backup & Recovery 10 Free Edition will give you a rich set of features that you can trust."

Free Backup Software: Paragon Backup & Recovery 10 Free Edition - Overview

It has been updated for Windows 8 now. Go here: