Dell Precision T5400 (Late 2007) - Manual (Page 160)

160 Adding and Replacing Parts
3 Rotate the card retention mechanism back into its original position; push
its tip so that its tab clicks into place.
4 Reconnect both sides of the P3 power-cable bundle that is attached to the
card retention mechanism.
Replacing the Front Panel
1 Align the hooks on the front panel with the corresponding holes on the
front of the computer.
1 card-retention mechanism
tab
2 card-retention mechanism
3 rotatable hard-drive carrier
3
1
2