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The next item that needs to be removed is the laptop's CPU. This is installed on the motherboard underneath the heat sink. To remove it, you must first remove the heat sink.
In the example model, there are four pressure screws holding down the heat sink. In other models there can be more, or less, but the principles are the same. Because of how these pressure screws work, it is best not to simply start undoing them. As you can see, they are always numbered in the order which they should be released. Another thing to keep in mind, however, is that if you fully release one screw the chances of others becoming cross-threaded is greater. I recommend that you only release each screw half way at a time, then go back and finish undoing them. Usually 3-4 screwdriver turns is about half of the screw.
Once the screws are released, grab the edges and lift off the heat sink.

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Note about other models: Some of the more high-tech model Dell laptops will also have a heat sink installed on the video card. This comes off in a similar manner. If you're ever in doubt about which things need to be removed from the motherboard for replacement and which don't, simply look at your replacement board as a comparison.
Underneath the heat sink you'll find the CPU. Before you can remove it from the socket, you first need to use a flathead screwdriver to give the release latch a turn (see image on the left). Once released, grab the CPU by the edges and lift it straight out of the socket. Lay it somewhere very safe with the pins facing up. Never touch the pins. If you have a spare antistatic bag lying around, now is the time to put it to good use.
When you go to place the CPU into the new socket later, there will be a marking on the socket and on the CPU that correspond - of a small triangle in one corner. This indicates a place where there is no corner pin, allowing you to line of the CPU correctly. In the absence of a marking you can visually confirm the location of the "missing" pin.