Originally Posted by Glymbol
Well if it's happening only in one game then I'm almost sure it's not mouse related. I had something similar in CS 1.6. It happened with any mouse, but was more noticeable at higher polling rate settings, so initially I though my mouse is causing this (the old one was 125Hz only). I tried many possible solutions over a few months, even reinstalled the OS to no avail. I was about to give up but tried termination of all non essential processes and services. I couldn't even connect to the net but was able to run the game and the issue stopped. Then I gradually started to turn on everything back one by one and found it was caused by some power managing utility (I'm on laptop). I uninstalled that and all works great since then.
I actually think I've had this problem also only in CS 1.6!
It doesn't even happen everytime I play, it's very rare.
I try to lower my polling rate to 500hz from now on, so let's see if that has any effect whatsoever...