you will need another Ubuntu ISO image alongside Zorin ISO image.here i have choosen lubuntu (700Mb).
1. extract WUBI.exe from UBUNTU.ISO file
2. put UBUNTU.ISO & WUBI.exe at Drive C://
3. Run WUBI and continue installing UBUNTU.
When it asks for a reboot to continue, just click reboot later.
Now here comes the tricky part.
1. goto C://Ubuntu/install/boot
2. replace
'VMLINUZ'
'INITRD.LZ'
'MD5SUM'
with the same files from your choosen Linux distro ISO file. Most of the time you can get those file from the 'CASPER' folder of the ISO file.
3.replace C://install/installtion.iso file with your choosen Linux distro ISO file.
Thats it. Now you are ready to install any Linux distro using WUBI.
Note. Some linux distro has different INITRD file extension like .GZ .XZ, etc; You will need to modify the C://ubuntu/install/boot/grub/grub.cfg according to the file extension.
