is the buzzing and is it those grinding sounds or just loud spinning type? Is it intermitten, or from starting up of the laptop till shutdown? or only when you are doing some software intensive stuff?
Did you check at the fan outlet to see if there's any dust clogging it? Usually a fan making noise when the processor is running faster, thus making the cooling mechanism to kick-in, or dust at the fan is making it hotter, thus causing the fan to start spinning faster, else, worst case is the dry-ness of the fan motor, causing grinding noise.
My Thinkpad that I've had for over a year is making some strange fan noises. It's coming from the top left. Even though the fan is buzzing the computer is not getting hot. Does anyone know if this is a repair that can be done without using a warranty?