League Of Legends Bug

hey guys, ive been playing LoL for a while now and recently i have encountered a problem, the problem is everytime i launch LoL it wont open the patcher or the main game it doesnt do anything, i have tried many things eg deleting stuff in the folder and taking my friends launcher and putting it on my computer but nothing so far has worked, until this morning when i opened it and it worked but now it doesnt work. someone please help!!! thanks :S :P :D