In Windows 7, you longer need third party software to burn ISO image discs.
Insert a writable disc in your PC; dismiss the dialog / program that auto-launches, if any.
Right-click on your "iso" file and choose "Open with > Windows Disc Image Burner".
When the application launches, select your CD / DVD burner drive.
Check "Verify disc after burning" to analyze for errors after it's been burned: the process takes longer, but saves time compared with an unbootable/corrupt image disc!
Click "Burn": time needed depends on ISO file size, CD writer speed, and your computer's performance - you'll have time for a coffee (avoid heavily using your PC during burning).
Once the process is complete, click "Close" and eject your CD.