Internet Connection Problems
If a black screen shows up your pc screen after champion select, and write something about your internet connection try to take off your firewall or your anti-virus protection or sometimes its all about your Modem router guys.. I had this problem but today i changed my router and now everything is ok try to contact with your ISP
Also you can spam the 'Enter' Key after champion select to get to summoning(also works but its not a permanent solution)
Searching for 2 todays for a solution and i wanted to share it with you guys