There are three fuse box locations on the W210. One is under the hood on the drivers side near the windshield. A second is on the drivers end of the dash (door must open to access). The third is under the passenger second row (rear) seat cushion. Each compartment should have a fuse chart which is a piece of cardboard and inserted near the fuses. It may not be immediately noticeable if you're not looking for it.

Most radio options include some electronics in the trunk area with only the head unit in the dash. So if the radio died after the accident that's a possible problem area.

Copies of the fuse charts are here:
http://www.benzworld.org/forums/w210-e-class/1349757-list-fuses.html

Also, Becker radios often have a fuse on the back of the radio. You will need radio removal 'keys' (cheap at dealer) to pull the radio and the radio code to restart it if the problem is a blown fuse.