I'm also getting this error - updated my sons xbox via dashboard today not been on xbox live since he had xbox. He wanted xbox live so added a profile and for some reason some games are not working ? thought it might be laser ,disk etc but some games work and others don't. My other son has a Xbox Slim 250gb and thats working fine with all disks no problem. Have sent a email to support - The xbox was manaufatured on 9/11/2006 and had been returned with a RROD failure some 2 years ago although has been working fine since todays update.