I have had SR4 a little while now and the first time I played it I got 91% in and my game suddenly froze when my friend joined and when I loaded it up again both me and my friends game save from when he came over (which convinced him to buy the game for himself) were gone! So I started it again and got about 20% in and it happned again as my friend joined again. Me and my friend play together frequently and we both manually save often and I have found no other incidents of this. HELP PLEASE