Regarding the claims of validity of clickwrap EULAs and similar "agreements"; it is relativelly easy to hack the installer on disk, or the web page as displayed by your browser, or the contents of RAM or video memory while the "agreement" is being displayed, and change the terms of the agreement or replace the text on the "I Agree" button by somthing like "I Do Not Agree"; they can never prove you really signed the same contract they originally wrote or that you signed saying you agree instead of saying you don't or somthing else.