Dell Precision T7400 (Late 2007) - Manual (Page 266)

266 Adding and Replacing Parts
6 Slide the sliding-plate lever to the right to release the shoulder screw and
slide the drive out to remove it from the drive bay.
1 optical drive 2 data cable
3 power cable 4 data cable
5 SATA connector on system board
3
2
4
5
1