Dell Precision T7400 (Late 2007) - Manual (Page 260)

260 Adding and Replacing Parts
7 Press down the release lever on the side of the drive carrier and pull the
Media Card Reader out.
8 If you are not installing another drive in the drive bay:
a Reinstall the empty drive carrier by sliding it back into the drive bay
until it clicks into place.
If you later decide to install another floppy drive or a Media Card
Reader in that drive bay, you can slide it into the drive carrier without
removing the carrier from the drive bay.
1 Media Card Reader 2 floppy drive/Media Card Reader
carrier
2
1