check your fuses to start...
do you have the on board computer? you may have accidently tripped the anti-theft device. if it kicks in, it won't let you start your car until either a) you enter the proper code or b) disconnect and reconnect your battery.
and BMW's do not spend more time in the driveway and/or repair shop. i have a bmw with over 350k, never a major problem. the worst was a muffler, and that was my fault. just fyi...