HP d325 Slim Tower Model Hardware Reference Manual page 16

Hardware Upgrades
2-6
6. Locate the cover latch. Pull up and hold the latch 1 to release the
computer access panel.
7. Slide the computer access panel back 2 about 0.5 inch (1.25 cm),
then lift the access panel up and off the chassis.
Removing the Computer Access Panel
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