How can I (re)install Ubuntu from within Ubuntu?
I am running Ubuntu 12.04, and I have a Ubuntu 13.04 on a USB drive.
I want to format my hard drive and install Ubuntu 13.04. I don't have a CD, and my computer won't boot from USB.
To upgrade from Ubuntu 12.10 on a desktop system:
No need for USB device. However, if you don't have internet connection it won't work.
You won't be able to do a format and install without booting from some external device.