On friday i bought an xbox 360 arcade. Today it had 3 of the red lights flashing on the ring of light. I am taking my xbox to game-stop to get a new system. I was wondering what accessories or anything else that i could buy that might decrease the chance of my xbox 360 arcade breaking or malfunctioning?

I recently bought an Xbox 360 Arcade with Halo 3. I’ve gone over many websites trying to find differences between it and a normal 20Gb Xbox 360, or is that just it. If that is the case, then will it play Xbox original games if I buy a 20Gb memory for it? Any answers would be greatly received.