Dell Precision T5400 (Late 2007) - Manual (Page 156)

156 Adding and Replacing Parts
4 Slide the front panel toward the top of the computer and then lift to
remove the panel from the computer.
Rotating the Hard Drive Carrier Out of the Computer
1 Disconnect either side of the P3 power-cable bundle that is attached to the
card retention mechanism: press the release latch on the P3 power-cable
bundle connectors beside the power supply and pull the two connectors
apart.
2 Press the card retention mechanism release-tab and rotate the card
retention mechanism so that it rests against the rotatable hard-drive
carrier.