Sony has acknowledged a problem with dust accululation around the cooling fan for this notebook. Sony addresses the cleaning of another notebook cooling fan, but doesn't offer advice on how to clean this unit. I have used compressed air and that has helped with dust, but I believe that there are a build up of "fuzz balls" around the cooling fan. Do I need to remove the back cover to see if there is a lint problem? How easy is this procedure? After the computer has been on for a while, it will randomly shut down. All power options have been reviewed and are set properly.