Dell OptiPlex G1 - Manual (Page 82)

Front-Panel Insert Removal (Mini Tower Chassis): Dell ™ OptiPlex ™ G1 Systems
To remove a 5.25-inch front-panel insert, follow these steps:
1. Hold the bezel with the front facing you.
2. From the front of the bezel, use your thumbs to press inward on the insert until it slides off the two posts.
To replace a 5.25-inch front-panel insert, position the two ring-tabs over the posts on the inside of the bay opening, and then press the ring-tabs over the posts. If
necessary, use a 1/4-inch nut driver to help push on the ring-tabs.