A recently acquired hard drive - a basically new drive - appears to have been causing my mbp to shut down randomly (different drive and the problem goes away). I ran a surface scan on it using tech tool pro 5 and found just one bad sector on the drive. I zeroed the drive using the binary 0000 pattern option in tech tool (1 pass) and ran the surface scan again and this time the surface scan gets the all clear. Should I be worried about the drive? Is it likely to cause the same shut downs on my mbp? I know the only way to know for sure is to try it, but I tell ya, installing a hard drive on the mbp is time consuming!!