Dell Dimension 8400 - Page 28

b. On the retention base locate the tab opposite the power supply. Press on the retention base tab until the heat sink pops up slightly.
c. Press out on the second retention tab while lifting the heat sink up and out of the retention base.
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3. Push down and out on the socket release lever.
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4. Open the processor cover.
NOTICE: Lay the heat sink down on its side.Do not touch or remove the thermal grease on the bottom of the heat sink.
NOTICE: If you are installing a processor upgrade kit from Dell, discard the original heat sink. If you are not installing a processor upgrade kit from Dell,
reuse the original heat sink and blower when you install your new processor.