ok!! heres my dilemma, Brand new starter, new battery, new alternator new Gas filter... the car used to work OK til the owner decided to install a CD player in it, it worked OK for a few weeks, now its not starting.. ok when it finally starts you can be on the road and it powers OFF while your driving.. Does anyone know what the problem could be?? or what the problem is...

Oh its a Land Rover Discovery.. '96