Dell Dimension 2100 System Reference Manual page 53

3.5-Inch Front Panel Insert
To remove a 3.5-inch insert:
1.
Remove the front panel
2. From the back of the front panel, press the release tab to the side.
3. Rotate the insert toward you, and remove it from the front panel.
Upper 3.5-Inch Drive
1 Insert
2 Tabs (2)
3 Release tab
.