I want to take off my motherboard and clean the dust out of it with a air compresser. Can I do that? My fan is running so loud
yes you can do that, better with a clean brush and a vacuum, but what model and make computer is that? There are many specific tutorials for certain computers.
A heat sink clogged with dust and dirt will make the fan run faster, shorten the life of the CPU. It's a good idea to clean it out once a year.