Some repairs on an Xbox can be repaired with a heat gun. Turn your Xbox off first. Take it apart. Remove all of the bolts and screws. Set them aside. You will need to remember where everything goes to reassemble it. Remove all of the heat sinks. Clean off all of the paste. You will only be heating the GPU. Do not use it on the CPU. You'll need Arctic clean and a cotton swab to remove all of the paste. When it is clean, turn on your heat gun. Set it for 1000 degrees. You can test it by seeing when it is able to burn a sheet of paper. When it is hot enough, then you are ready to use the gun on the GPU. Heat the GPU for 20 seconds. Keep it moving the entire time. Then, flip it over and heat the other side. Then, press down on the chip and hold it. Allow it to cool. You can blow on it or use compressed air. When it has cooled, reassemble it.