Follow my instructions.
First: Don't use the programme you are using to communicate before starting a game.
Second: When it crash, right click on your internet icon at the bottom right corner of your desktop and click on Troubleshoot problems.
Third: If no problems is appear and the problem still resist, try to shut down your firewall. For a tutorial on how to proceed, go make a research in your browser.
Fourth: If the problem is still there, instead of restarting your client loading screen, close your client and re-enter your username and password and try to reconnect to the game.
Fifth: Go into Internet Explorer Options and advanced then, check on the Enable Internet 3rd-Party extension browser.
Sixth: Go make a research on how to reset your internet Protocoles IPV4 and IPV6
Seventh: uninstall League of Legends and remove every files about this game in your personal computer Driver. Then reinstall League of Legends.
Eighth: Goin device manager and update your internet driver.
9th: This is for extreme condition only: recover your operating system to 0 then re-install your OS completely.
If nothing works, this mean your pc does not support Adobe Flash Player and Adobe Air. And so you gotta have to ait until a new client comes out in the next season.