I was having hard drive problems with my mid-2010 unibody Macbook Pro. I bought a new hard drive and set up it using a SATA to USB cable before installing. Everything worked great so long as I had the drive hooked up via USB, but when I installed it in the machine, the machine would not boot from it. If I held down option+R during startup, it would not find the new disk.
So I ordered a new SATA cable for the Macbook Pro and installed it. Still nothing. Am I missing a step or should I assume the problem is somewhere else in the computer? Would love your thoughts/wisdom.