Dell OptiPlex 7000 Micro Service Manual page 46

Steps
1. Remove the screw (M3x3MM) that secures the internal antenna assembly to the chassis.
2. Remove the captive screw that secures the internal antenna cover to the chassis and lift it away.
3. Push the internal antenna assembly inside from the opening on the back view and lift it away from the chassis.
46 Removing and installing components