a few months ago i had one of my friends, whom i no longer can contact,soft mod my xbox. yesterday out of nowhere i turned on my xbox but i got an error 13 (this is with no disk inside the drive at all) so what i did was try and play a game so i put in an official version of nfl 2k6 in and it worked perfectly fine. the next time i decided to play it showed me error 21 (this is with a original game or dvd in the drive)I've read the forums on the error meanings and the hotswap but I'm unsure what exactly i need to do to fix this problem. I'm completely unexperienced with this kind of thing....can anyone help me, what should i do and how to do it?????....PLZ HELP ME