Downloaded windows 7, how to burn an iso image to my cd?

Use a CD burning program, like the free and excellent ImgBurn. When you run it, select "Write Image File to Disc" and it will ask you to browse for the .iso. Note that Windows 7 is a DVD image, NOT a CD image. I hope this helps.

I prefer http://isorecorder.alexfeinman.com/Vista.htm

"If you're on windows: CDBurnerXP - fast, easy and free: http://cdburnerxp.se/download.php

On Mac: Disk Utility handles itself pretty well

On Linux: I use Brasero"

You need a DVD or thumb drive.