Checkout "Next" button...

I am having trouble with the checkout process for payments. After a user submits their address (billing and/or shipping), they have the option to choose their payment method. When you click on the method, it doesn't chance the payment method choice by the "next" button. Then, after hitting the "next" button, it changes the choice and does nothing else.

I tried this with using only one payment plugin and with both paypal and credit card plugins. Initially, the paypal plugin would redirect me to the paypal site correctly, but that stopped working for some reason. I've uninstalled all of the plugins, components, and modules and reinstalled it... and have uninstalled it again. Is there something I can do to try to fix this?

Thanks.