MacOS – Internal Hard Drive Not Visible

UPDATE: I purchased a dual hard drive adapter for swapping with the optical bay, and installed it in my machine with the original 500GB SATA III that Apple shipped with the laptop. So far everything is working just fine, and I have two working hard drives in the machine (triple booting Lion, Yosemite, and Windows 7 via Boot Camp). The second HDD is displaying 6.0 Gb/s link speed, with a 3.0 Gb/s negotiated link speed. I understand that even though the HDD is SATA III, it's dropping down to SATA II speed; but so far there aren't any problems with the disk running, and I can boot Lion from it without any issues. Will post any further developments.

Apparently RAM I installed months ago didn't want to play nice with the new SDD. Switching back to the old ram got the computer to boot no problem. (Weird, because I previously had no issues with the RAM before upgrading the SDD)