Don't overtighten screws on reassembly - especially on plastic models. Card readers have tiny parts which can disappear on a typical floor. On card reader models, remove two screws from under small caps near the AC adaptor socket. On non-card reader models, remove two screws from inside the battery compartment. A hair dryer might help to soften the adhesive.
Additional screws hold the spine to the front case.
When the spine is removed, all of the keys and switches will be freed so be careful. The silicon grease under the slide switches is meant to be there - don't clean it off. Be sure to line up the pins and holes in the keyboard, spill guard sheet etc. If the keys don't feel right, your alignment is incorrect. Be especially careful when disassembling card readers.