-noforcemparms -noforcemaccel

noforcemaccel – reverts to desktop mouse acceleration settings. For the most part (when it comes to gaming and precision accuracy) mouse acceleration is a fickle feature. The noforcemaccel command will make sure Half-Life does not try and manage mouse accel when it is disabled in your windows options.
When to use? When mouse acceleration is disabled on your desktop and you want the same results for your in game experience.

noforcemparms – reverts to desktop mouse button settings. What does that mean? Usually when you start up Half-Life (or in this case Counter-Strike) your mouse configuration will switch to application mode, allowing the assignment of keys already assigned to your desktop (like mouse3). This variable turns that feature OFF. There is really no benefit to this command, and in actuality it is quite buggy at times.
When to use? When you are experiencing difficulty with button assignments. A part from troubleshooting this command has no practical use, despite popular belief.

noforcemspd – uses desktop mouse speed settings. Noforcemspd forces Half-life to use whatever speed settings you have applied to your desktop via mouse properties. Whatever the value, Half-Life will use it as guidance.
When to use? When you want your out of game speed to set the bar for your in game sensitivity. Think of sensitivity as a speed (de)amplifier.