Unfortunately the Nspire CX family is ''horrible'' to disassemble.
# Remove all the screws on the back. They're Torx T6 and Phillips.
# You need to carefully heat up the glossy plastic bezel to soften the glue underneath (unfortunately I don't have an exact temperature. Be careful you don't start melting the plastic)
# Then you need to very carefully bend the plastic bezel away to access the two screws hidden underneath. Be careful not to snap or warp the plastic while taking it off.
# This will reveal two screws near the TouchPad.
# [link|https://cdn.ti-planet.org/forum/gallery/image.php?album_id=63&image_id=8334&view=no_count|Here's what it should look like|new_window=true]. (Image from tiplanet.org, a French calculator community)
# Once those two screws are remove you can start prying the two halves of the calculator apart.
These calculators are so difficult to disassemble that TI will drill holes in the front bezel of their prototypes to access the screws easier.