HP Pavilion Slimline s5220f Supplementary Manual page 20

3 Disconnect all peripherals and cables, including the
power cord.
4 With a screwdriver, loosen the side panel thumbscrew
on the back of the computer.
5 Slide the side cover toward the back of the computer,
lift it off, and set it aside.
4
6 Locate the three tabs that secure the front panel to the
7 Swing the panel open and off the computer.
— Removing and Replacing the Hard Disk Drive
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computer. Pull each of the tabs out slightly, away from
the computer, to release the panel.