Getting rid of Proprietary ATI Driver

[Schiz0]

Hey,

I installed Ubuntu 8.0.4.1. It said I needed the restricted ATI
driver, so I enabled it. It downloaded and installed the package, then
I rebooted. Now xorg crashes about 1 minute after I can see the
desktop, every single time. I'd like to get rid of the restricted
driver. Is there a way I can do it via commandline? I don't have
enough time to uncheck the 'restricted drivers' box before xorg
crashes.

Thanks.