The zero insertion force (ZIF) connector often causes trouble for beginners. ZIF connectors are used to secure delicate ribbon cables, such as FFC (flat flex cables) or FPC (flexible printed circuit) cables.
To disconnect the cable, use the tip of a spudger or your fingernail to flip up the small locking flap. Then, you can safely pull the cable out.
The flap may be either on the same side as the cable, or on the opposite side. Inspect your connector before you start prying.