BMW Repair: Keyless Entry, remote keyless entry, bmw emblem

Question
I purchased a used 2000 BMW 528i.  Last four vin numbers are 1316.  The keyless entry does not work and there are no FCC no. on the remote.  No one can figure out how to open it and replace the battery.  Can the battery be replaced or will I have to get a new remote keyless entry?

Answer
Jackulene, what shape is the key? Square or Diamond shaped? Does it have the BMW emblem in the center for the lock button or does it have the little LED in the upper right corner? New keys are around $150. The square key has a battery in the back the diamond shaped key (newer) is charged when in the ignition and the car on. E39 had a problem with the Fuel door lock actuators shorting out and blowing the central locking fuse which also controlled the remote key functions. Please check all fuses especially in the rear of the car near the vehicle battery. I thought it was fuse #35.
-Evan