HP ProBook 5220m Notebook PC - Manual (Page 88)

5. Press down on the door (2) until the until the release latch (3) clicks.
6. Slide the lock latch (4) to the right to lock the door into place.
NOTE: You can identify the lock latch by the red marking on the latch.
7. Replace the battery.
8. Turn the computer right-side up.
76 Chapter 6 Drives