I understand good and well how to use sata cables to run any type of hard drive, BTW, I was intrigued that you found a 2.5. I made an assumption. And that WAS MY INADEQUACY. as far as your issue the drive is not your problem, the size, connection and such wouldn't be relevant.
Put all int games on ext. using any up to date manager, and erase all back up managers and comgenie
Then reinstall backup managers, (OPENmanager 2.1d is the best of those) Gaia has a different game folder, if that is what you are using then install first, then reinstall the rest. this should work.
If the games were there and playable, then just disappeared then maybe altering files is your issue, that's pure speculation on my part.