You might have downloaded ISO files on the net before and wonder what it is. Basically ISO files are virtual copies of CD/DVD that people created. Please read this guide to create your own virtual CD. This guide is intended for personal use only and please do not support piracy.
Here I will teach you how to create a virtual CD drive that could read ISO files.
1) Install Daemon Tools Lite, restart your computer if it asks you to. It will create a new drive in your computer (Go to My Computers and you should see it).
2) After installation, you'll see the daemon tools button in the notification area.
3) Right click on the icon and select Virtual Devices > Device 0 > Mount Image...
4) Browse and select the ISO file you want to read with your virtual drive.
5) You may now use the virtual CD as though it is a real CD which is just slotted into your CD drive :) This is particularly useful for computer games that require your CD to be slotted in your computer at all times.
To unmount the virtual CD, repeat step 3 but choose 'Unmount Image...' instead.