League of Legends has encountered a problem. Please re-install League alpha client to try again.

I recently (unfortunately) experienced hard drive failure. I tried to re-install League of Legends, and it worked the first time (while I was running Windows 8), but after I got sick and tired of not having a start button I upgraded to Windows 10. Unfortunately, this lead to the above problem. The initial legacy client installation worked ok (after a couple of tries), but while trying to upgrade to the new client it just comes up with this error message: League Client Error- League of Legends has encountered a problem. Please re-install League alpha client to try again. I don't know what to do. Any advice or help would be greatly appreciated. No League is no fun. [zombie-nunu-tears]