Please define the diff; SERIOUS question, as I wish to know the diff btwn the tw. (My 'O' key fell off, its difficult to type with an 'o' (and this is a brand

Please define the diff; SERIOUS question, as I wish to know the diff btwn the tw. (My 'O' key fell off, its difficult to type with an 'o' (and this is a brand new machine - ticket open.. fOrgive the O weirdness in all my text.