Disable pop-up hints

Go to the options in CounterStrike : GO and disable the Game Instructor Messages as seen in this screenshot:

This should stop the game from annoying you in the future.

Another method would be to open config.cfg in your CS GO Folder (after you removed the mentioned read-only flag) with a text editor of your choice, such as Notepad++. You can find the file in X:\Steam\SteamApps\common\Counter-Strike Global Offensive\csgo\cfg (X being the hard drive you installed it on). Then find the line where it says gameinstructor_enable and set it to 0 or, if it is not there, add gameinstructor_enable=0 at the bottom of the file. That should do the trick.

It is now: This PC/Windows C/ windows (86x)/Steam/userdata/(OWN ID SHOULD BE ONE FOLDER)/730/local/cfg

Go through the config file and check if you don't have any binds to enable gameinstructor. (That was my problem I got so frustrated; my buddies just did bind mouse1 "attack;gameinstructor_enable" or something).