Installing A 3.5-Inch Hard Drive - HP ProDesk 400 G1 Microtower Hardware Reference Manual

6. Disconnect the power cable (1) and data cable (2) from the back of the hard drive.
7. Remove the four 6-32 mounting screws (1) and slide the drive out of the bay (2).

Installing a 3.5-inch hard drive

1. Remove/disengage any security devices that prohibit opening the computer.
2. Remove all removable media, such as compact discs or USB flash drives, from the computer.
3. Turn off the computer properly through the operating system, then turn off any external devices.
4. Disconnect the power cord from the power outlet and disconnect any external devices.
CAUTION:
as long as the system is plugged into an active AC outlet. You must disconnect the power cord
to avoid damage to the internal components of the computer.
5. Remove the access panel.
Regardless of the power-on state, voltage is always present on the system board
Installing and removing drives 29