Create bootable CD from ISO
I think the first step is to make sure the .iso file is bootable. From Windows 7, you can burn the .iso right from an Explorer window. Make sure you select the .iso file you want to burn before you try to click the Burn buttons.
You can use the free ImgBurn to do that. Here is a walkthrough explaining how to create bootable CDs with ImgBurn.
Assuming you're running a previous version of Windows before Windows 7:
InfraRecorder is free CD Burning software...