Power off the computer and unplug it
Remove the CPU cooler
Clean the CPU surface and cooler base with isopropyl alcohol and a lint-free cloth
Let both surfaces dry completely
Place a small pea-sized dot of thermal paste in the center of the processor
Do not spread the paste unless the paste manufacturer specifically instructs it
Reinstall the cooler straight down onto the CPU
Tighten the cooler evenly in a cross pattern
Reconnect the cooler fan or pump cable
Power on the computer and verify normal temperatures