Hi, Installed some Nvidia-drivers (not sure exact which package) and rebooted. The elementary OS logo is visible after boot but then i only got a black screen. Can't switch to any other ttys with ctrl-alt and the function keys. Got access to the system via a live usb, but then what? I would like to avoid a reinstallation of the os. So how can I find and remove/disable the suspected package/drivers? Any help is appreciated