Hardware Problem, SATA connector

I own a MacBook Pro 15 Inch mid 2009.
Recently it would not boot into the operating system,
I thought the hard drive had failed because of it's age.
I bought an OCZ Vertex 2 (because buying Vertex 3 I
would not get the advantage of SATA 3.0) and installed it.
I booted through a USB with Lion 10.7.3 and went to Disk
Utility. I tried to erase, partition, everything but it could not
unmount the disk. I put the SSD into another MacBook Pro (same
specs and year) and it could erase and install fine.

So when it was installing I put the HDD of the other Macbook Pro
into the first MBP, but it would not boot, it just stayed on the Apple
loading screen. I held down option and tried to boot into the
Windows 7 partition on the hard drive, but I got an error saying
that there was difficulty reading the hard drive.

When the SSD was finished installing I put it back into the first MBP and
tried to boot, but it just stayed on the loading screen. At this point I knew
that nothing was wrong with the HDD or SSD, but rather with the internal hardware. Does anyone know what might be causing this? Would it be worth it to try buying a OWC Data Doubler and putting the SSD into there, or is something wrong with the Logic board? Remember that it booted fine into the USB installer of Lion, it just wouldn't boot into anything connected via the SATA cable.

Help is much appreciated!

Thanks