If you’ve never discovered this yourself, you’re about to see one of the reasons why I’m sold on Opensuse.
Hit CTRL-ALT-F3 (or a CLI terminal of your choice; that’s my habit). Log in as root, then enter “init 3” to ensure that X isn’t running. Then whack “enter” one more time. You may need to log in again as root; do so.
Now enter “Yast” to run the text-mode tool, which can do everything that the GUI can – you just use the TAB and arrow keys to get to what you want, instead of the mouse.
Go to Software Management, set the “filter” (upper left) to “search.” Assuming that you’re using 11.1, a box will appear; tab into that box and enter “Nvidia,” then tab one more time and press “Enter.” All Nvidia-related packages will appear in the box to the right.
Tab into the box and use the up/down arrow keys to highlight any NVidia driver that has “i” (installed) to the left. Press the space bar on each such line to mark it for uninstallation. (You may get some warnings; that’s OK.)
The goal is to get the current incorrect drivers uninstalled. Select “OK” when you’ve marked them and they’ll be removed. When it’s done, it’ll ask if you want to install or remove anything else; tab to “no” and press “enter.”
Now you should be able to tab to the “Hardware” selection, and then to “Graphics Card and Monitor” to install at least a working default display. Once you’re done, reboot. This should restore you to the condition that existed right after intial installation. When it comes back up, you can repeat the steps that you did earlier when you installed the wrong driver.