LoL launcher not opening patcher

Whenever I open the launcher and the "League of Legends" Icon pops up in the middle of the screen, usually in about 5-10 seconds, the patcher will open. I've redownloaded the launcher and the same thing happens every time: after about 2 minutes of not doing anything, the icon disappears. I know it's not connection errors because I've reset the modem and the same thing happens. Can anyone tell me how to fix this?