Major Client Issues

OK. So, yesterday when trying to get on to play a game, the client would not launch. I tried to uninstall and then re-install, but when I searched for League, it didn't say that I had it downloaded at all. I went to the website to try and download it, but it told me that I had to get rid of the other files I had on my computer first. I ended up searching through my C and User drives deleting every single file I had associated with Riot, and eventually it let me download the game. Today, it was acting the same, and I had to go through the same process over again. This time it wouldn't let me load into the game though. Does anyone have any clue how to help me?