HP ProBook 5220m Notebook PC - Manual (Page 61)

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.
10. Align the tabs on the service access door (1) with the notches in the service access bay.
11. Slide the service access door down (2) until the release latch (3) clicks.
12. Slide the lock latch (4) to the right until it locks.
NOTE: You can identify the lock latch by the red marking on the latch.
13. Replace the battery.
14. Turn the computer right-side up.
15. Reconnect external power and external devices.
16. Turn on the computer.
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