MacBook Pro 15" (A1226) Broken Hard Drive Cable
It looked like someone had tried to install a new drive in the laptop. The cable had been bent so that it broke at the point the two sections diverge from the base. Diagnosis was difficult as the split was not easy to see at the start.
Repair went without a hitch. Drive installed and OS booted on first attempt.
Whatever it is you are trying to do, google it and watch the video. Someone's done it before and posted it on YouTube.