Remove the fan and heatsink from the laptop.

The heat sink for the CPU can be tough to remove. Use an opening tool to help you pry it from the board.

Remove the old thermal paste from the CPU using isopropyl alcohol.

Put the alcohol on a cotton swab or paper towel, don't pour directly onto the computer.

Apply thermal paste to the top of the CPU. if you need instructions on how to remove and replace thermal paste follow this guide here.