Thank goodness someone else is having this problem! Mine was working fine in Act 1 but now during Act 2 I can't click on anything except the main header. I have done a full reinstall of the client and have tried to repair it yet nothing has worked so far. My friends' clients are working, so I have no idea what to think of it. I hope Riot looks into it!
This is what mine looks like. It's a bit different.
NOTE: I can still play games and do other things. I can look at my profile & match history and I can access the shop as well. It's just anything on the main page is inaccessible save for the "Bilgewater Act 2" which I assume only works because it is an external link.
Definitely bumping this!