When you create a system image
using Windows 7 Backup and Restore
, it creates a virtual hard drive vhd-file which contains all your files and folders, and some xml-files which contain the information needed to restore your system using this image. See the image:
Notice that in this case there are two vhd-files; If your OS is not located on the first partition of the first hard drive, System Image Backup needs to save the boot information on a separate vhd. This also occurs when making a system image of a virtual machine. If this happens, the bigger vhd is your actual system backup.
Installing this system image as a second hard drive makes it possible to pick up and extract a single file or folder. It is a very practical tool if you make a system image often enough; it allows you i.e. to restore a file or folder you accidentally deleted, without the need to do a complete restore. Please notice Virtual PC has a 127 GB sizr limit for virtual hard disks. If your system image vhd-file is bigger, use Disk Management to mount image and extract files as told here