ISO files, also called images, contain exact duplicates of CDs, DVDs or Blu-ray discs. An ISO file saves every piece of data -- even hidden files and boot information -- exactly as it appeared on the original disc, making ISOs the best way to fully copy one disc to another. If you have an ISO file on your hard drive you can also mount it, loading the file as if it were a physical disc.
Creating ISO Files
Neither Windows 7 nor 8 supports creating ISO files from optical discs natively. To make your own ISO, you need additional software. Numerous programs can make ISO files, including disc burning suites bundled with new computers, such as Nero. Alternatively, download software such as ISO Recorder or IsoCreator. Keep in mind that creating ISO files of commercial discs may violate copyright, and that many discs contain measures to prevent duplication.
Mounting ISO Files
Windows 8 allows you to load an ISO file, avoiding the need to burn it to a disc. Right-click the file and choose "Mount." The contents of the file appear in a new window, to which the system assigns a new drive letter. To unmount the file, right-click the drive in the Computer window and pick "Eject." Older versions of Windows do not support ISO mounting natively, but other programs can add this feature.
Burning ISO Files
To burn an ISO file to a disc on either Windows 7 or 8, right-click the file and pick "Burn Disc Image." Pick the drive to use from the drop-down menu if you have more than one disc burner, and insert a blank disc into the selected drive. Optionally, check "Verify Disc After Burning" to have the system make sure the burn finishes without errors. Press "Burn" to start. After the burn finishes, reinsert the disc to view the contents of the ISO. Note that merely copying an ISO file onto a blank disc won't work -- you need to use the image burner.
Aside from disc images, ISO might also stand for the International Organization for Standardization, or may refer to one of the many standards that group manages. The term ISO for disc images actually comes from the group's standard for optical disc file systems, ISO 9660.