RInput program helps to get rid of unsteady mouse acceleration in game. The article about turning off acceleration could be found here.

How to use:

1. Launch RInput.exe


2. Write hl.exe in the opened console


3. Launch CS

Console will close itself in a few seconds.
You can launch RInput.exe after CS, but it could lead to some bugs.

Also there is a way to save your time:

1. Copy RInput.exe and RInput.dll to any folder with a short name (without spaces and only with English letters!), for example C:\rinp\


2. Create a text file on your desktop and write down this:
   
   START C:\rinp\RInput hl.exe
EXIT
   
   In Save as menu specify extension as All files and name it (for example) rinputlauncher.bat and save on the desktop (or wherever you want), text file could be deleted.


3. Now you can just launch rinputlauncher.bat and then CS.

Note 1: If you play on classic servers, be aware that RInput could be considered as a hack. There are not so many of these servers, but anyway, be careful.

Note 2. You can launch CS through rinputlauncher.bat as well. For example, for Steam CS just edit it like this:

START C:\rinp\RInput hl.exe
START steam://rungameid/10
EXIT