my patcher is messed up

I opened lol on a computer that had it already installed, just had to download patch 5.5. I left for 1.5 hours, came back, 12 mb left, 99% 0 kbps, and unspecified error. I exited and re-opened the patcher, and it was scanning files for an hour. I exited and re-opened, it has to install league again. wtf rito