Windows 7 System Backup is a backup utility that comes free on most versions of Windows 7. It is a good way of backing your entire windows 7 system to an external hard drive.
Please note that you will have to create a Windows 7 System repair disk in order to get your system backup restored on to a new hard drive since
there will be no system on a (new) empty hard drive.
How it works is, you would need to take a full backup of your current system, then if your hard drive becomes unusable for some reason, you would put in
your windows 7 system repair CD/DVD - THAT YOU CREATED (or you can use the USB version instead of a CD/DVD)
and boot up the computer
from that. The system repair program will ask you whether you want to restore from a backup (The one that you created) or if you want the system repair
program to try to fix windows.
Even if you do not backup your system with the Windows 7 system backup tool, creating a Windows 7 System repair disk is still highly recommended.
Video Tutorials of how to make a system restore disc as well as backup and restore your Windows 7 system using the Windows 7 system backup:
More about a system backup can be found at: