Remove the fan from the panel by removing the four 6-32 flat head screws. Observe the fan and filter as you are disassembling it. The fan will be installed in the new fan panel the same way. An arrow on the fan shows the direction of the airflow. It should flow in, toward the main printed circuit board. Retain all fan mounting hardware in a secure location. Discard the old fan panel. Check the filter. Clean it with a vacuum if needed.