Movement issues

[Professor America]

I'm having a very odd problem.  For some reason when I try to walk, it locks up.  Even when the key isn't pressed, it still keeps walking, and I can't do anything else.

It isn't my keyboard, because I've tried playing other games, and I've tried changing the controls.

I don't want to reinstall the game, as I'm too far into it.

*edit* I apologize. This was posted in the tech demo section. That's the wrong one. I'm playing Penumbra: overture.