HP Compaq Presario,Presario 7954 Supplementary Manual page 44

8. To add a 3.5" hard drive, place the new hard drive in the top drive
compartment and secure the drive with the bottom retaining screws.
9. Locate and connect the spare power supply cable. Spare power supply cables
are provided with the system.
10. Locate the data cable that is connected to the primary hard drive installed in the
lower slot of the drive cage, under the diskette drive. This data cable is
equipped with a spare connector approximately midway down the cable.
Carefully insert the connector into the receptacle on the back of the secondary
hard drive.
11. Replace the computer cover.
12. Refer to the manufacturer's instructions supplied with the new device to
complete the necessary software installation.