a similar instance happened to me. first started with halo3 and soon after I got halo wars. worked fine for a week or so, next thing i know I boot it up to get online and I get the RRoD.  Once I got my xbox back, it made a ratting sound...this discouraged me, but everything worked ok..  So..i'm playing one day and I get "disk read error" and this started happening to me after every match (required a reboot, would allow me to play one game, then happen again).  I call xbox and they said to send it back, but she told me to boot up the console w/out the harddrive, which I did and haven't had any problems since...knock on wood.