If you wish to boot your ISO image, you have to make sure that your CD-ROM is in the correct boot order above your virtual hard drive. You should now see that your ISO image has been transformed into a regular CD and it is ready to be used. Click on “ Choose a virtual CD/DVD disk file“, look for your ISO image, select it and click “ Open“. Then, on the last section to the right, click on the CD icon (I am using VirtualBox 4, in VirtualBox 3 the icon looks like a little folder). In the middle column, select the “ Empty” CD-ROM. Next, in the settings window you are going to select “ Storage“. Select your image and then click on the “ Settings” icon.
As you can see in the picture below, I already have a virtual machine created for Windows 7. In order to run an ISO image you must have a virtual machine already created.
