I have a 1999 E39 520i which just stopped starting after parking it in the Garage. When I try to start it, it just cranks na na na na na... but it won't start. It check the fuel at the valve and it is there and I can even hear the fuel pump. I checked the spark at the plugs and it is NOT there. It is a manual transmission so I tried to PUSH it and it starts with no difficulties. What can be the possible cause of this problem?? Looking forward to your help on this.