Dell OptiPlex 990 (Early 2011) - Manual (Page 13)

Front Bezel
3
Removing the Front Bezel
1. Follow the procedures in Before Working Inside Your Computer .
2. Remove the cover .
3. Pry the front bezel retention clips away from the chassis.
4. Rotate the bezel away from the computer, to release the hooks on the
opposite edge of the bezel from the chassis.
13