Open a Laptop
You don't need to open it to clean it out. Using a toothpick and an air compressor is the way most professionals do it. With the laptop powered off, GENTLY stick a toothpick into the fan to prevent it from spinning. Failure to do so could burn-out the bearings or even cause the fan blades to snap when you blow the dust out. Next, using an air compressor, blow the dust out of the fan intake and the exhaust openings. Also blow out ANY openings on the computer. Don't be afraid, no amount of air is going to dmaage anything in the computer if the fan is stopped.