Client keeps sporadically crashing

I have had an issue that last several months where my client crashes when loading into a game. I go through champ select fine. The pre-game loading screen will then come up, but instead of seeing champ images and load percentages all I get is a black screen. In time, I get a popup window that tells me that says "Unable to connect to the server. Please check your network connection and attempt to reconnect to you game." I have tried restarting my client and my computer, neither works. The only solution that I have found had been to wait an unspecified amount of time (sometimes an hour, sometimes not until the next day). This problem is unpredictable and happens once every few days. I have other friends at my college and in my building who play League and don't have this problem so I know it doesn't have anything to do with my area, and I my room is in a different building from last semester so I know it's not my ethernet port. I have also tried uninstalling and reinstalling my client, to no avail. Does anyone know what this could be?