Once in a while you get hold of an ISO file (an ISO file is basically just an image of a CD/DVD/BLUE-RAY disk) and need to access the content of this file, there are several ways of doing this;
1) You can burn the ISO file to a media and read it this way.
2) You can extract the ISO file to a folder using a utility (WinRar is very good at this).
3) you can mount the ISO file as a virtual CD/DVD eg. use Deamon tools lite.
I would suggest option 2 or 3.
Anyhow, David Davis has written a nice beginners guide on the subject, so be sure to check it out at;
http://www.windowsnetworking.com/articles_tutorials/Mounting-ISOs-Windows-7-Free-Tools.html