HP Compaq 620 Notebook-PC - Manual (Page 107)

c. Gently press the memory module (3) down, applying pressure to both the left and right edges
of the memory module, until the retention clips snap into place.
NOTE: If you removed a memory module from the expansion memory slot before removing the
primary memory module, replace the memory module in the expansion memory module slot.
11. Replace the bottom door (1) sliding it securely into place (2).
Upgrading a memory module in the primary memory module slot 95