Comment # 4 on bug 965028 from Stefan Dirsch

> Whenever upgrading leap with nvidia drivers, when the kernel upgrades, the 
> system will no longer boot to the gui on reboot, and the nvidia driver breaks > until it is reinstalled.

So reason is, that you've installed the driver manually. Unsupported (works
when using the RPMs). --> INVALID

Feel free to try again with using our documentation.

  https://en.opensuse.org/SDB:NVIDIA_drivers

[...]
The packages contain the correct 'supplements:' so Zypper will find the correct
modules for your card. Unfortunately on openSUSE Leap 42.1 these
'supplemements' are being ignored by default by YaST (boo#953522). Therefore
you need to select 'Extras/Install All Matching Recommended Packages' in
'Software Management' for autoselection and installation of the appropriate
NVIDIA driver packages. When using 'zypper inr' you're not affected by this
issue on openSUSE Leap 42.1. 
[...]

Uninstall the driver before by running

  nvidia-installer --uninstall

My guess is that you've messed up your system by chosing random nvidia
packages.