Another thread. . If I cannot get anyone to fix my iMac, I would attempt to do it myself, what would I have to lose, right? Problem is: HDD. Disk verification comes up good, I hear no unusual sounds, but if I try running something like a torrent app, the disk usage spikes like crazy and everything freezes. It's as if the disk it too slow to keep up or something. It never used to be like this. I had run an apple hardware test before to see what it would say, and I got this error: 4MOT/1/40000003: HDD\ Currently It displays: 4MOT/2/40000004: HDD\ This is definitely for the Internal HDD, but my question is: Does this mean it's definitely the HDD? What other hardware components are related to the HDD that could be causing this? Anything to control or run it aside from the HDD itself? I'm just wondering because if I try to open this, and replace the HDD -- will that work, or would I be overlooking another issue? I'd rather know more about the hardware before attempting to open it up and fix anything. I would rather make sure I fix the problem the first time.