^
EDIT: It doesn't happen as the champ screen loads, it starts when I select a champion.
EDIT #2: It happens when I click on Katarina... that conniving wench!
Basically, a few seconds after I get on the champ select screen, the client freezes, and I can't do anything about it, except wait. After the first time, I forced my PC to shut down, thinking I could reconnect to the game I was in... Nope, now I have a "Leave," on my match record. 
This doesn't happen anywhere else, not the shop, profiles, etc, and it doesn't happen with Custom games, only Normals, and Co-op vs. AI champ selects. I don't play Ranked, so I don't know if there is an issue there either.
Please help. u.u