hi there, im a normal user like you so dont take this from granted
normaly windows warns up people when its the last resort
so your drive normaly have several bad sectors remapped or it may have a weak head that does this
i would backup your data to another good functioning drive as soon as possible ( dont turn off that drive) it may be too late then
install hard disk sentinel and let us see the prints please ( post in tinypic, imageshack, etc)
