Yes. If Windows is doing something to "make it bootable" then it's probably not burning the .ISO image. You want the image burned exactly as-is. That's why it was saved as an .ISO image. If it's supposed to be bootable, that functionality is already a part of the saved image. And (to give a specific example) if a big part of the content on the CD you burned is a file ending in .ISO, then it wasn't burned as an image.