Welcome to LinuxQuestions
There are many free ISO burning applications but windows 7 does have this feature built in. http://gizmodo.com/5138148/win-7-tip...built-right-in
An ISO file is a byte for byte image of a CD or DVD. By selecting burn as image the file contents including the boot code will be written to disk. If you view the contents of the CD or DVD you will lots of files and folders. If all you see is a single file it was not burned correctly.