Cant Log in

I seem to be having this issue, where after I click the "Launch" button on the client and it takes me what should be the log-in screen I only get a black screen on the Client. I am on the NA servers and this only started happening after the latest patch. It happens every time, and to quit league I have to use the Ctrl+Alt+Delete task manager to end the program. The task manager says the League Client is running fine, but I only get a black screen and can not log in.

System Specs: Intel i7 CPU 930 @ 2.80GHz RAM: 6.00 GB 64-bit Operating system