Desktop Composition is in the Compatibility tab.
To create an image file, you will need a CD/DVD burning program. Nero, or Alcohol 120%. There's a few more, but Nero is among the best.
If you don't have either of these (or any other burning program), you won't be able to do it. But if you do, I can tell you how (though making a CD/DVD image might not even fix your problem).