I see. I have a feeling that the PlayonMac stuff sitting in that folder might be the cause for the game not starting. Somehow it might be overriding your OpenGL settings and trying to enforce them in a Mac-like execution. This is mere speculation though. Since you say you've tried multiple things, they could be somehow conflicting with each other.
First I want you to try downloading an OpenGL test like GpuTest or FurMark to see if OpenGL works on your machine. Don't run these tests for too long; anywhere below five minutes is fine unless you have absolute confidence in your machine. These will really stress your machine but will tell if OpenGL works or not.
If the above works, then you're gonna have to do this:-
I recommend you just delete that Freespace 2 installation and start from scratch. No need to reinstall Windows though. (Phew!) You know how to do this, right? Install Freespace 2, then download the latest 3.7.1 build (either in my previous posts or from the nightly builds). Download the latest mediavps. Download the campaigns. Download wxlauncher.
Yes, you might have some of those files already, but unless they've been updated in the past month or two I'd recommend redownloading them, even if they are big downloads (mediaVPs can be big). I did redownload myself. Let's see: Builds go in main Freespace 2 folder or a subfolder if you prefer, MediaVPs go in "mediavps_3612" folder in the main Freespace 2 folder. wxlauncher goes in main Freespace 2 folder. Campaigns go in whatever folder they extract as, BUT make sure they only go 1 level deep, ex: Freespace2/Sync .