I have a 530XI 2007 with Nav. I cleaned it this weekend, left the doors open too long and the battery died. I disconnected the battery while troublshooting and now the computer will not start. I tried to reboot the computer by hittting on the mut\eject and it does shut offan back on but will not complete the reboot, all I get is the BMW insignia on my screen. I am occasionally getting a battery warning but would this stop the computer from starting?

 

is this happening while the engine's running?

what happens after you see the BMW insignia on the screen? Does it switch off? If the car thinks the battery is low, it'll switch the iDrive off, and will limit the fans to 75% of normal power.

 

change your battery