Dell OptiPlex 745c (Early 2007) - Manual (Page 65)

8. Attach the SATA connector removed in step 5 to the first hard drive.
9. Locate an unused SATA connector on the system board and attach a data cable to this connector and to the second hard drive.
10. Replace the computer cover (see Replacing the Computer Cover ).
Drive-Panel Inserts
If you are installing a new floppy or optical drive instead of replacing a drive, remove the drive-panel inserts.
1. Follow the procedures in Before You Begin .
2. Remove the drive panel by sliding the drive release latch downward to open the panel. Then remove it from the hinges.
1 data cable 2 hard-drive system board connector 3 power cable