Most Acer models, if you flip the thing upside down and take the screws out on the larger panel, you should have access to the fan. Get a can of air and spray around this area, cleaning out the fan and surrounding area. Disable the fan before spraying in it to make sure it doesnt over spin. Use the end of a paper clip. I shouldnt have to add but I will, make sure the laptop is unplugged first and the battery removed.