In order to access the CPU, the CPU cooler fan must be removed.

Using a Phillips #0 screwdriver, carefully remove the four screws located in each of the CPU cooler's four corners.

Disconnect the fan's power cable from the motherboard.

If you are having difficulty please refer to your motherboard's user manual for assistance.

Gently lift and removed the CPU fan from the motherboard.

Be sure to clean off the portion of the underside of the fan that was in contact with the CPU off using isopropyl alcohol. This will remove any old thermal paste to ensure a clean connection during reinstallation.

You should now be able to fully see and access the CPU. If not, you may have done a step wrong and should revisit a previous step.