The .iso files can be mounted in Windows 8 and Windows 8.1, without Daemon Tools.
All you have to do is to click on the .iso file, notice the top pink option called “Disk Image Tools”. Click it, and then click on “Mount”.
Notice from My Computer, a new tab with the virtual disk (the .iso file).
Now you can restart your PC/laptop and let the virtual image to run (in case you are trying to install a new version of Windows, like Windows 10 preview).