Well I got Halo 2 for the PC for Christmas. I was very excited, as this is the one Halo game I haven't beaten. But when I went to play it, the mouse was constantly looking right, moving me in circles. I changed the mouse sensitivity, the mouse itself, restarted the game, restarted the computer, and then it worked. I was playing it later, and I believe I moved the mouse quickly, and it got stuck in the looking right. I re-started the game and all was good. Later (again) my brother hit the desk with a small base-ball bat (he wasn't trying to hurt me, just bug me) and it got stuck in the looking right again. I restarted the game and it was fine. Now I'm on the third level, and I saved+quit because I was getting tired. Now when I start the game, it looks left and down, but I can't even use my gun or grenades (which I could do before). I installed the drivers for the mouse (its a Microsoft Wireless Laser Mouse 5000), but that didn't even help.

I've restarted my computer a few times, and the game a few times, but it isn't working.

I'm running Vista Ultimate x64 bit, and the looking left+down does not happen in menus or pause screens.

Anyone have a guess to what this is? Google didn't help me

I have that problem with a lot of wireless mice. It happens in a lot of games, and the only solution I've found is to change the mouse out.

Thanks for the reply, but it didn't work. I took the batteries out of the wireless mouse and plugged in a USB mouse. Then I tried to play the game and the same thing happened.

EDIT
Found out the same thing happens in the Games For Windows Live Dashboard.
I'm trying to re-install Halo 2 now
EDIT 2
Didn't work

EDIT 3
Turns out, that having USB controllers plugged in (such as guitar hero and game pads) caused this. I unplugged them and it works. Plugged them back in and it didn't

SOLVED!

For the record, a similar thing always used to happen to me, where the mouse would randomly jerk to the corners of the screen, so ingame I'd randomly start looking up into the sky or ground.

I'm using a wired USB mouse, but the problem was that I didn't have a good mousepad. Just for the record, 'cuz it always annoyed me.