I think my mid 2012 MacBook Pro 2.9 i7 8GB 750GB hard drive is dying. I have around 250GB of free space and the MacBook is becoming really slow, getting slower over time. If the MacBook is on for over an hour or so it becomes almost unusable and transferring files to a USB3 stick are moving at about 5GB an hour, which would normally take only a minute or two. If i then restart the MacBook I get the stop sign (circle with line through it), which I am guessing means it can't access the HDD. If I leave it off for an hour or two, I can then use it again, but only for an hour or so before the above starts all over again. So what do you guys reckon, is it the HDD or something else? I am only guessing it is the HDD as this has happened to two other MacBook's of mine and both times replacing the HDD fixed it.