Changing key fob battery on a 2007 range rover sport

You need to cut the seam of the key with a razor blade, right around the entire key. Once you've done that you can pop the key open. It's usually just bad solder contacts from the battery to the circuit board.

Most Likely your FOB is fine anyways.. The problem with the remote not working 80% of the time is a corroded wire in the passenger side kick panel ( it will be covered in blue tape ) sorry I forget what the wire color is.. It's been a while.

Should be a very small screw holding the fob together. I would find a Land Rover forum like this one and ask the question. Doing a search on the forum you will likely find an answer. And a lot of invaluable information even many dealers will not know.

http://landroverforums.com/forum/