Comments - mema

1. Create a New desktop Icon for gmod
2. Right click on it and go to properties
Yours may say something different, used -gamelaunch or something
3. Under path it will say "C:\Program Files\Valve\Steam\Steam.exe" -applaunch 220 -game "c:\program files\valve\steam\SteamApps\SourceMods\gmod9"

this is what it should be changed to, assuming your path is the same.
4. Change it to look like this "C:\Program Files\Valve\Steam\Steam.exe" -applaunch 215 -game "c:\program files\valve\steam\SteamApps\SourceMods\gmod9"