Dell Dimension 2100 System Reference Manual page 63

The heat sink in your computer will be similar to one of those pictured in the
preceding figure. To remove and replace the microprocessor and heat sink:
1.
Remove the computer cover
2.
Rotate the power supply
3. Locate the microprocessor socket on the
4. Release the metal clip that secures the heat sink and fan assembly to
the microprocessor socket. Then remove the heat sink and fan
assembly from the microprocessor chip.
5.
Disconnect the fan
6.
Remove and replace the microprocessor chip
7. Unpack the heat sink and fan assembly included in your upgrade kit.
NOTICE: Ground yourself by touching an unpainted metal surface on the
back of the computer.
8. Peel the release liner from the adhesive tape that is attached to the
bottom of the heat sink and fan assembly.
9. Replace the heat sink and fan assembly.
NOTICE: When you install the heat sink and fan assembly, make sure
that the heat sink is flat against the surface of the processor while you
are installing the clip. If the heat sink becomes tilted when you install the
clip, excess heat can damage the processor.
a. Place the heat sink and fan assembly on top of the
microprocessor chip.
b. Orient the securing clip and hook the shorter side of the clip over
the tab on the top edge of the microprocessor socket.
c. Press down on the top to the fan to snap the clip over the tab on
the bottom edge of the microprocessor socket.
d. Connect the fan to the system board.
.
.
from the system board.
.
system board
from the socket.