WinCDEmu is an open-source CD/DVD/BD emulator - a tool that allows you to mount optical disc images by simply clicking on them in Windows Explorer. If you have downloaded an ISO image and want to use it without burning it to a blank disc, WinCDEmu is the easiest way to do it.
The project is no longer developed. Last version, 4.1, released on September 29, 2015, can be still downloaded from GitHub
Top 3 alternatives