installation

Hi,
I have 2 problems.

Firstly I had Zorin installed as a Dual OS with Win10 but after a Win10 feature update ZorinOS was deleted.
Then although I reloaded Zorin it does not run from the boot screen, only Win10 loads.

Secondly I decided to install Zorin on a separate volume. Which is fine until I receive the message (No root file system defined, please correct from partitioning menu.) At which point I'm stuck.
I think a solution to problem 2 would be best but would be grateful for any solution.

You need to mark the partition as "root." The symbol for this is: /
You select it from a drop down list, which also includes a bunch of other stuff like ext2, ext4, swap etc. Think of / as the equivalent of C in Windows. I believe if you right click on the partition you will bring up the drop down list.
.

You will only see Win 10 loading because it will probably change the power settings back again so that Win10 never fully shuts down, but sleeps until you boot again - in case you are wondering why Win 10 boots so quickly. Also if Zorin was installed in Legacy mode, it won't be seen either, even on Windows 7 - I have 7 pro 64-bit on hot swap bay drive and because Windows Boot Manager is active I have to press the key to get to BIOS to boot to Zorin by pressing F8 (Drive List) then choose the drive that I know has Zorin on. Check your BIOS and Power setttings (especially the hidden ones!)

Thanks for your quick reply and help. "/" enabled Zorin to load but still didn't open, so I enabled" boot in legacy mode" but this disables "secure boot"; I hope that's ok.
Then I was unable to mount the "c" drive in Zorin, so in Win10 Power Mode/ Change Advance Power Mode Settings I unticked Fast Start Up. That seems to have done the trick. I've posted this in some detail in case someone else has the same problem.
Once again thanks for all your help.