I've heard that Unetbootin provides installing a distro straight to Hard drive instead of USB. Should I just select Hard Drive as the picture shows and click Ok or there is something else to do?
The main purpose of Unetbootin is to create an installation media.
But it does not create the Ubuntu installation media properly anymore.
Use Ubuntu Disks tool (
gnome-disk-utility) to create the media instead.
Open Disks - select Restore Disk Image from the menu on the top right.
Choose the ISO file and the USB drive to write it to and start restoring.
When you have to create the media from within Windows :
Open command prompt as administrator and execute:
diskpart list disk select disk * clean create partition primary active format fs=fat32 quick assign letter=**
Note : * = number of USB drive | ** = select a free drive letter
Mount the ISO file and copy the content to the USB drive.
Boot from the USB drive and start to install Ubuntu.
It would be more worthwhile to acquire a small flash drive and boot from there instead. Unless, of course, your BIOS does not support boot from USB.
Unetbootin is designed to create "bootable Live USB drives".
Within my knowledge, I do not believe it is designed to install a distro.