First ups system specs:
Nvidia 9500GT 1GB
12GB Crucial RAM
1TB WD HDD
System was previously running 10.8.4
Ok so here is my issue, and I really hope someone can help as I'm at wits end. I've had this machine running perfectly since SL, through Lion & ML, original install method (for ML) was vanilla using Kakewalk 4.5. Everything worked fine until I installed the 10.8.5 update from the App Store, as I'd done for all previous updates. The update went smoothly, rebooted and after the the grey apple logo, the screen went black, not in a powered down state, but the system was definitely 'turned off' even though the power was still on. After some investigation (and many MANY reinstalls), I tracked the problem down to the nvidia drivers as the culprit (NVDAGF100Hal.kext, NVDAGK100Hal.kext, NVDANV50Hal.kext,NVDAResman.kext and NVSMU.kext) If I remove these from S/L/E I can boot just fine, though I'm stuck at a low resolution & the card isnt recognized. If I leave them in the system bounces me to that weird black screen, if I remove some of them (I tried diff combinations in the even it was just one kext) it just hangs. I tried using the version of these kexts from an earlier image of my machine when it was working and was met with the same result. I tried going back into the bios to recheck my settings, everything was as it should be for this board nothing was changed, yet even trying to boot using my original Kakewalk install USB stick wouldn't work until I went in and removed those kexts from the S/L/E on the USB drive. As a test to see if the update had somehow managed to bork my video card (IDK how that would even be possible) I tried swapping out several different ATI & Nvidia cards, the result for the ATI cards was a system hang at (PCI configuration) and the Nvidia cards all displayed the same issue as the 9500GT. I've finally managed to get everything almost back to where it was, but the graphics are the last hurdle. Has anyone even seen anything like this? Is it possible I need to load some other drivers, or am I just hosed at this point? Thanks for any assistance that can be offered in this regard.
I should also mention that I have tried changing graphicsenabler to both yes and no, neither made a difference.