Mouse Skipping, please help!

[Spielberg]

I began playing HL2 yesterday, and everything was fine.

But there are certain points in the game where whenever I walk over them, my mouse skips and I find myself looking either directly up or down.

This wouldnt be a major inconvenience if it didnt happen every 5 steps I make.

I dont know what the problem could be, but I know it doesnt happen to me with any other game except for HL2 and CS:S.

Any help would br greatly appreciated.

 

[Spielberg]

*bump*

I gotta get an answer for this.

Im playing the game, but its a night mare to start looking up and down in the middle of a firefight.