Hello, the key automatically recharges whenever the engine is started.
It's possible that you'll need to press the lock button twice, depending on how you've set up the central locking system.
BMW may need to re-program the key if it still doesn't function.
When my CD player acts up, all I have to do is remove the discs and reintroduce them before it starts working again.
Even though it's probably obvious, have you double-checked the boot to make sure there's a DVD player in addition to the disc player? Its possible that no longer being there is the cause of your lack of reception.