Entire Computer Freezes in Beta Client during Champ Select

I just tried to launch in Legacy client and works like a charm, but the last 3 times I tried to play ranked in Beta Client, I get dodge penalty because my entire computer freezes and I have to restart my comp. during champ select. It gets to about the third ban and BOOM everything freezes, I can still hear my computer whirring away but non-responsive. Thought you'd like to know..