Dell OptiPlex 745c (Early 2007) - Manual (Page 66)

3. Select the drive-panel insert in front of the drive bay that you want to use.
4. Gently press the release tab of the insert to remove it from the drive panel.
5. Reattach the drive panel to the front of the computer.
The drive panel only fits one way.
Floppy Drive
1 drive panel 2 release tab 3 drive-panel insert
1 optical-drive panel insert 2 floppy-drive panel insert 3 holder for shoulder screws
CAUTION: Before you begin any of the procedures in this section, follow the safety instructions located in the Product Information Guide.