Radio/tape Cd Player problems of the 2003 Land Rover Discovery

I have 2003 Land Rover, Discovery car that requires constant replacement of the navigation system and its radio/cd player. This is my fifth replacement since the purchase of the car. In addition to this, the engine oil constantly leaks. . . Took it in for repair numerous times but the problem continues. The engine light is always on. . . . Took it in a few times and the dealership repair center said it was an electrical sensor problem. The brake and abs lights would come on and go away on its own. Since March 2010, the brake and abs lights decided to stay lit. Will take it in for vehicle inspection at the dealership. Just yesterday, all my passenger windows can not be moved up or down with the window controller. A similar problem was reported to the manufacture numerous times on both the driver and the passenger windows. They were replaced each time it was taken in. This is a lemon car and I should have had it reported back in 2003 when I first purchased the vehicle.