In this guide, the actual laptop is HP Compaq 6520. You also can use it to remove the keyboard from HP Compaq 6520S 6720 6720S laptop.
1. Turn off your HP Compaq 6520 / 6720. Disconnect the power adapter and remove the battery. Unscrew the two screws securing the keyboard.
2. Remove the three screws in the battery bay, you need to use the special screw driver for these screws.
3. Detach the clips of the keyboard cover in the battery bay.
4. Open the computer as far as possible. Now, you need to pry up the keyboard cover from its left or right side. You can do it at any position circled in the picture.
5. Loose the battery cover but don't remove it, there is a cable which is connected to the mainboard.
6. Remove the keyboard and lift it a little, you can see the keyboard cable. Release the zero insertion force (ZIF) connector and disconnect the keyboard cable
Note: If you don't mind your old keyboard, you don't need to loosen the keyboard cover, just pry up the keyboard directly.
Now, you can remove the keyboard from your laptop. Reverse the procedure to install the new HP Compaq 6520 / 6720 keyboard.