alot of people used cans of compressed air that you can buy at bestbuy or compusa for like 4-5bucks and just spray the dust off/out
i mean the inside where u download stuff and u cant clean it your self disk cleanup,defrag wont clean it all
Many techs do very meticulous backups and just reformat hard disks/reinstall the OS a few times a year. It doesn't take long at all if you know what you're doing and have the appropriate equipment.