I recently bought a Turtle Beach Ear Force X41 headset for the Xbox 360. But, being as big a nerd as I am, I also connected it to my PC. However, while using the headset during a LoL match, my computer will freeze and I have to do a hard shut down. Even I said I was crazy when I thought it might have been the headset the first few times it happened. But after the 3rd time, I switched the main sound output off of the headset and haven't had an issue since. I think this may have more to do with the path of the sound output than the headset itself. Normally I would think this is a hardware issue but LoL seems to be the only program that has the issue.
My sound output, in this situation, goes through my video card(Nvidia GeForce GTX 580) and into my monitor(Samsung SyncMaster P2770FH) through HDMI. From there I use a toslink cable to output into a toslink switch and then another toslink to the headset's receiver (as it is a wireless headset). I'm using Windows 7 64bit and all the items listed are updated with the latest drivers. Let me know if you need the rest of my specs.