Its an problem with CFG file, as some thing happen, in League of Legends, and that resolution which isn't supported by your monitor (some random for example 1921x1085 instead of 1920x1080) it would say to your monitor that the resolution isn't supported.
Whatever the name of .cfg file is rename this file to that name (as i don't have lol installed, i had it) and replace the original file.(for example mine is Config.cfg and your is configure.cfg, change my config to configure).
First run game with bots and change the settings.
After changing settings (in game) end game, and exit lol.
After that go back to CFG and right click, properties and Tick Read-Only and click ok.
Now it shouldn't never change the settings after that, but if you are gonna fiddle with settings again, you have to untick that and change settings and re tick that box.
Heres link to download
https://mega.nz/#!EaQmWQYT!38PeBzhWeUVWCyXsjakAbe6acST1iiKbMs34K2gpmdw
The .CFG file is downloaded from here https://www.gamingcfg.com/config/game.cfg.
Where i used to download for CS 1.6 and CS:GO
And my friend also had GT 210 and that would happen.
(lol soo many updates, sorry for spamming guys).