If you leave it paused for too long, it freezes.

If the xbox is idle for more than 45 seconds to a minute it will crash, causing you to lose all unsaved progress. Some games are downright unplayable eg: 'Half Life 2' (which loads the whole map and then you play through the level) so when you enter a new map, it loads the map for a while, and it is as if the game has been idle, and it reports that the disc is dirty or damaged, or just freezes in the loading screen.

It used to not read any discs, but we replaced the dvd player and that fixed it completely for a while. now this is happening. A very annoying problem, to say the least, especially when it locks up while you are saving. Then the file is corrupted and you must restart the game from the beginning. This happened with 'Tony Hawk's Project 8', and 'Burnout: Revenge'.