I'm sorry if somebody else posted this before... but for those who don't know it here is an explanation.
1)Start Steam, log-in to your account
2)Go to the tab LIBRARY->GAMES, find CS:GO right click properties, then click the LOCAL FILES tab and click BROWSE LOCAL FILES.
3)You will see the launcher .exe usually only called "csgo", make copy of it somewhere, delete it LEAVE THE FOLDER OPEN.
4)Click start write CMD, right click CMD and click copy then go back to the folder and click paste(local files folder).
5)Rename CMD to "csgo" (without the ").
6)Now start it, it will open up a cmd window minimize and keep what you do :P
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Whenever you actually wanna play CS:GO replace the "fake" "csgo" launcher with the original one.
And yes you can play other games on steam while this is working...






= profit