Client wont launch after patcher has completed patching

Normally, my patcher patched to 100% and nothing happens, so i close it and relaunch the client, and on the 2nd time it patches to 100% and league launches. Recently, it has been patching to 100% and nothing happens, even if i relaunch the client. Also, after it has patched to 100%, it starts going over showing : ETA -2 or whatever number of mintues it is. Idk why this is happening please help !