A lot of software is available as ISO files or IMG files and most folks would like to install this directly without having to go through the hassle of burning a DVD. This can be done by mounting the ISO file as a drive and installing from that drive.
Windows 7 and older Windows do not include the capability to mount a ISO file, but there are tools that offer this feature. The best I have found is Virtual CloneDrive. Download it, install it and any time you need to mount a ISO file, right-click it and choose Mount. When you are done and unmount it by clicking on the Virtual CloneDrive icon in the system tray.
Tried with: Virtual CloneDrive 18.104.22.168 and Windows 7 x64