Bought this xbox a few days ago from a friend of mine. It worked fine and everything. I also got DOA4, Oblivion, and Quake 4. Anyways.. it started to trip up a little at the startup of DOA4 but just for a second and then the entire rest of the gaming was fine. Then it started doing this shit where.. im on the dashboard and i put DOA in.. and it says "Reading" and then it just goes to "Open Tray", like nothing is in there. I tried again and DOA worked.. played it for awhile and then I was done. I also put in oblivion and it worked fine. Now its doing it all the time. I thought it was just my DOA disc so I decided to play oblivion. Turned it on, same thing. "reading" and then "open tray". My xbox will now play Audio CDS but NO dvds. Not games OR dvd movies. Help?