Ako ne radi zbog monitora onda je moguce da ti je ostala stara rezolucija koju ovaj ne podrzava ili neki problem vezan za to.
Kreni od toga da probas da pokrenes igru u rezoluciji na kojoj ti radi monitor.
Evo kratak tutorijal sa neta ako znas engleski, dole promeni rezoluciju sa 1920x1080 na onu na kojoj ti radi monitor
Open Windows explorer
Go to (default location)
C:\Program Files (x86)\Steam\userdata\YOURSTEAMID\730\cfg
Open
cs2_video.txt
Find the lines below in the file and alter them as needed, leave the refreshrate_numerator as is, you most likely don't need to touch it unless it's wrong (i.e. 60 instead of 240).
Example is for 1080p 60hz (your refresh rate might be different)
"setting.defaultres" "1920"
"setting.defaultresheight" "1080"