Be Warned:
If you play id Software games (Quake, Wolfenstein, Doom) - there is a chance that your mouse pointer icon will always be in the center of your screen (in-game).
Apparently, it's related to DiVX - although, by removing my codecs, the problem still occured.
My solution?
Delete Doom 3. It's terrible.
Just warning you - if you play those games...