One of these free programs is beloved by many Daemon Tools. It understands all formats of virtual disks, easy to use and doesn't take much resources from the computer. In addition, it can create disc images and record them to disk.
For that would be to install it, follow the link http://www.disc-tools.com/download/daemonclick on the Download. After the program is downloaded, run it and install, following the instructions. Computer after installation need to restart.
After reboot your system will see the virtual DVD-ROM, which you can insert disk images. You can work with them in the same way as with conventional discs. In order to insert (mount) the drive, left click on the circular icon with the lightning in tray. Choose only active row with the drive letter and locate the file with the game. If you have the image in a different mds/mdf/mdx format, in the section "types of files" select the desired. Now you only have to install the game, as is done with conventional disc. In order to unmount the image, you press left click on Deamon Tools icon and select "Unmount all drives". Without this you will not be able to remove the image from your hard drive.
Alternative to Daemon Tools could be the program Alcohol 120%. She can do the same thing, but it has significant negative for its use need to pay. You can read it on the official website of the company http://www.alcohol-soft.com/