So I fixed my slight mouse delay by turning acceleration and Vsync off in the ini. files. Everything works like a dream now out in the wide open world of Skyrim, but I recently found a little vampires cave and whenever I walk into it, my mouse sensitivity on the up-down axis drastically increases, meaning that left - right sensitivity is fine, I think, but the up down sensitivity is ALOT higher. This also happens when I sprint ( But I think that the mouse sensitivity is supposed to decrease when you sprint anyways, but only by one direction? I'm not so sure.. )

Anyway, back to the problem. This only happens inside this cave, you see. Right outside of it the mouse is fine. When I go inside, it happens. I don't know if it has to do with the fact that the cave is quite narrow? I've heard of other people having this issue, but not to this extent and not depending on location.

I remember having this issue in Oblivion and there was something in my driver that I had to set up but I can't remember what it was.

I'm having the same problem, with a slow mouse cursor but it's taking a back seat to figuring out why its crashing right off the start for no reason with no error and flickering textures. >.>