Keyboard/Mouse don't work in game

[MardukRising]

I've checked google, steam forums, and this forum, and as far as I can tell, no one else has had this issue. When I first start the game, and navigate through a few menus, everything is fine. And once I get into the game, and actually spawn - nothing. My keyboard and mouse do not respond to the controls in the game. I can not move, look around, open any menus. I can alt tab, and close the game. At one point, I died, and I could navigate in the menus again - but only then.

I really want to play this game, and enjoy it. I and a few friends downloaded it, and intended to play it together. They, so far, can all play it fine.

What is wrong? Any ideas?

I'm on Windows XP, if that helps at all.

Edit: Correction, my mouse works - I can use it to click things in the chat and stuff, but the keyboard does not work at all, other than typing messages.