Check the DS slot at the back and make sure that none of the pins are bent and that there are no "foreign bodies" in there.
If it is new and under warranty send it back if not you will have to get a quote to repair it, or you will have to take it apart and have a look inside, you will need a special tri screwdriver for this
Some people will say don't open it up you will make it worse but how can you if it is all ready broken and repair costs too much?
