Dell Dimension 9100 Service Manual page 35

b. Set the retention mechanism aside in a secure location.
4. Use a long Phillips screwdriver to loosen the two captive screws on each side of the heat-sink assembly.
CAUTION: Despite having a plastic shield, the heat-sink assembly may be very hot during normal operation. Be sure that it has had sufficient time
to cool before you touch it.
5. Rotate the heat-sink assembly towards the rear of the computer, and remove it from the computer.
1 heat sink and fan shroud assembly
2 captive screw housing (2)
6. Place the heat-sink assembly on its side in a safe place.
7. Disconnect the system fan cable from the system board.
8. Ensure that all cables have been removed from the routing clips on the top of the system fan assembly.