Your kernel log is saying that the Nvidia driver is not cleanly installed, so please use the 'Additional Drivers' app to remove it, then reboot, then reinstall it using the same app.
Please also consider installing a newer Ubuntu release. The one you have will reach end of standard support next year.
Thanks for the bug report.
Your kernel log is saying that the Nvidia driver is not cleanly installed, so please use the 'Additional Drivers' app to remove it, then reboot, then reinstall it using the same app.
Please also consider installing a newer Ubuntu release. The one you have will reach end of standard support next year.