728i bmw had a flat battery, now need a code to start the car

I have a 1999 728i bmw and had a flat battery. I charged the battery and now can't start my car as the display reads code ----? I have lost the code and the dealership are charging a lot of money just to resolve this issue. Can any one help?

I have heard of this issue before.. Have u tried disconnecting and reconnecting the battery again? try simple codes like 0000 and see what happens. Otherwise you may be looking at the dealer.