HP Armada 7300 Reference Manual page 57

6. Close the computer if it is open and turn it upside down.
7. Use a Torx T-8 screwdriver to insert the original hard drive
security plate, or use the screwdriver supplied with the
computer to insert the tamper resistant security plate.
CAUTION:
always reinsert either the original hard drive security plate or the
tamper-resistant security plate to prevent the hard drive from
accidentally disconnecting.
Inserting the Hard Drive Security Plate
To prevent damage to the hard drive or loss of data,
Working with Removable Drives 6-7