Well this sounds like a hardware compatibility issue, somewhere between your hardware, drivers, and OS. Hard locking your machine is generally caused by some hardware failure, not a bug within the game. It could be trying to run a particular code path on your video card causing the hard lock, such as utilizing HDR Bloom. It could be the way it goes to full screen conflicting with a corrupted windows installation. It could simply be that a file is corrupted on your hard disk and is causing Windows to lock up attempting to read the file. But I'd be looking at testing your hardware or reinstalling your operating system to resolve this issue, as I don't believe there's anything that can be done in the game's code/files.