Hi, recently my last gen macbook pro (15 inch) has been from what istat pro says writing to the hard drive for no reason, i havn't a clue what its writing especially when im doing nothing on it and its not downloading anything either. Yesterday i was forced to clear some media files out to make space for a security update yet that morning i had about 3.5gb's of free space! Is it possible ive got a virus or what as its my main computer. Any ideas wold be gratefully appreciated.