Generally newer laptops have CMOS batteries attached to the motherboard by one of three methods:
1. Battery in recess under keyboard or under a door on the bottom stuck with adhesive and a short cable that plugs into motherboard.
2. Battery in a clip similar to desktop (usually a standard CR2032)
3. Battery soldered to motherboard in some manner (rare, but normally this is the case w/lower entry-level systems)
When taking apart the laptop take pictures where necessary of cable routing/positioning. Use a 1 or two small pillboxes and put the various groups of screws in pillbox sections--mark down which screws are in each section preferably in the order they were removed.
Patience and observation is a great virtue in doing this work!