The game ran fine for me the first time I played it, until it (ironically) froze right after the boss battle with the frost dragon. Ever since then, whenever I try to launch it, it's so slow as to be completely unplayable. There's about a 2-3 second lag for any key press, the title screen takes a good thirty seconds to fade in, etc. If I try to start a new game, I can't even skip the opening cutscene, since the D key does nothing. This is the only game I'm having problems with. I'm running Windows 7 Pro 64, with 8GB Ram and NVIDIA GeForce GTX 560 Ti. Any help would be appreciated!

Take a look at this thread: Master List of Known Bugs

I read on the Discussions there's a lot of "first flawless, then something"-experiences so it's possible after a first play the game just corrupts itself somehow, it's hard to pinpoint what exactly when barely nothing changes.

What you could do is making sure your primary GPU is used by the game and not some intergrated stuff that might be in your CPU if it's relatively modern.

Reboot at least once.

There's some issues with certain device inputs too so if you use a controller or have multiple keyboards you could try and connect only one at a time and see if you could produce the same issue with all of them or it's actually connected to one device.

What CPU and device input do you? A controller or a keyboard?

Hi Nirth and thanks for the response! After restarting a few times it finally seemed to "stick" and I've been able to turn the game on and off with no issue. For the record, I've been playing with just a mouse and keyboard.