Re: Removal of Nouveau driver crashes system after boot
You can boot to runlevel 1 by pressing the 'e' key in the grub menu, and appending a '1' (one) to the end of the kernel line. Then press 'b' for boot. From single user mode, you can either install the removed nouveau RPM from USB (once you mount it). Or, if you have a static network config, you can 'init 3' and then use yum to install it (if you use NetworkManager then that most likely won't work).
As mentioned, use the rpmfusion repo for NVIDIAs binary drivers. There is no need to remove nouveau first (and you probably shouldn't just to avoid the situation you are in), since rpmfusion provides an easy way to switch between the two (a good thing... as you would probably agree at this point).