HP PV738AA Hardware Reference Manual page 29

Hardware Reference Guide
4. A latch drive bracket with release tabs secures the drives in the
drive bay. Lift the release tab on the latch drive bracket 1 for
the drive you want to remove, then slide the drive from its drive
bay 2.
Removing the Drives
5. Remove the four guide screws (two on each side) from the old
drive. You will need these screws to install a new drive.
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Hardware Upgrades
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