Not booting in standard, but other kernel version OK

[Aravisian]

You can set default boot to an older kernel using this method:

[HOW TO] set an older kernel to default boot

You may need to use an earlier kernel than the current kernel used by Zorin. This method allows you to set the kernel that you will boot into by default. To set the new kernel to default: Boot into the kernel you wish to be Saved. Open terminal and run: sudo nano /etc/default/grub Change GRUB_DEFAULT=0 to GRUB_DEFAULT=saved Hit enter to drop down a line. Add GRUB_SAVEDEFAULT=true ctrl+x to exit, then the y key to say yes to save, then the enter key to save as current configuration. Ru…

Or, you can just uninstall the later kernel that is grabbing priority.