I broke X
I wanted to install the NVidia linux drivers on Debian. So I edited that file the determines which runlevel you boot to so I would boot to runlevel 1. Now, the instructions read to change the runlevel to 3, but doing that started X for me. So, I went back to runlevel 1 and started the installation there, even when the NVidia installer warned me that installing in runlevel 1 might cause errors. And now it doesn't work.
This is how it is now: when booting the screen first goes black. Then if you touch a key or something there is a dialogue box that says that X malfunctioned, and asks if I wants to see the log (yes / no). (I don't know why it is trying to start X, it should still be in runlevel 1.) The screen is filled with strange artifacts here. Selecting no (or after looking at the log) brings you to a login prompt.
I tried to switch back to the backup config file, but no effect.
I can't format since this is my brother's computer and he has important stuff on it. Am I screwed?
I allowed the installer to configure stuff, if it matters.
Note that I'm a Linux noob, so be gentle. Which reminds me: how do I save the log and get to it from my Ubuntu Live CD?