Moving this discussion to the Premiere Pro Hardware Forum.
The steps to enable your GTX 660 ti are very simple - find and delete (or rename) the file cuda_supported_cards.txt file. Then, the Mercury Playback Engine (MPE) will allow he benefits of your hardware. The benefits for hardware (GPU) assisted MPE is significant for CS5, CS5.5, and CS6. And most likely, it will help for CS??? whenever that comes out as well.
>message on the lower right about the display adapters stopping working
To keep your current card working until you replace it (if the problem really is the software driver, and not a hardware problem) go to the AMD/ATI site and check for a newer driver for your card
Do NOT rely on Windows Update to have the latest information
OK. Thank you. And what do I rename it as? I unfortunately really need a step by step as I don't want to mess it up.
Renaming it will keep it around, but in a way that the software does not recognize it. So, when I said delete it or rename it, you can rename it to any other name.