Dell XPS 8960 Service Manual page 58

Steps
1. Remove the screw (#6-32) that secures the front I/O-bracket to the chassis.
2. Rotate and remove the front I/O-bracket from the chassis.
3. Disconnect all the cables that are connected to the system board.
4. Remove the nine screws (#6-32) that secure the system board to the chassis.
5. Lift the system board at an angle and remove it from the chassis.
58 Removing and installing components