Laptop overheating and suddenly shutting down?

The rock is cooking.

My Acer Aspire 5930 laptop started overheating and shutting down again so I checked the temperature and found that one of my cores was missing while the temperature of the remaining core went negative. That can't be good. Time to clean the heat sink and change the thermal compound. This will help the laptop to keep the temperature down.

1) Unplug everything. Turn the laptop over and remove the screws.

2) Remove the back cover.

3) Remove two screws that are holding the fan in place and disconnect it's power cable.

4) Remove the fan.

5) Notice the dust on the heat sink.

6) Carefully unscrew the remaining heat sink screws. Don't try to remove them.

7) Gently lift and remove the heat sink. It might be stuck because of the old thermal grease.

8) Remove the old thermal grease from the heat sink. I used a knife.

9) Don't clean the thermal grease from the circuitry, you might damage the small SMD components. Just add more grease! I bought my thermal grease on ebay.

10) Put the heat sink back and screw it in place, then put the fan back in, screw it in place and connect its power cable.

11) Put the back cover back and screw it in place

Congratulations! You're done. Fire it up and enjoy. Here are the before and after temperature readings: