HP 520 Maintenance And Service Manual page 44

Spread the retaining tabs (1) on each side of the memory module slot to release the memory module.
4.
(The edge of the module opposite the slot rises away from the computer.)
Remove the memory module (2) by pulling the module away from the slot at an angle.
5.
NOTE:
memory module slot.
Reverse this procedure to install a memory module.
36 Chapter 4 Removal and replacement procedures
Memory modules are designed with a notch (3) to prevent incorrect installation into the