Dell OptiPlex 740 User Manual page 160

1 cable release tab
6. If you are removing a Media Card Reader, disconnect the data cable.
7. If you are removing the Media Card Reader, remove the hard drive (see
8. Disconnect the data cable from the system board.
1 Media Card Reader data cable
9. Pull up on the drive release latch and slide the floppy drive or Media Card Reader towards the back of the computer. Then lift up to remove the drive or
Media Card Reader from the computer.
Installing a Floppy Drive or Media Card Reader
2 data cable edge connector
Removing a Hard Drive).