Today I was trying to install the new Ubuntu 14.04.1 from a USB Live, and I tried with the UNetbootin tool, after I reboot my computer I just saw the UNebootin menu but nothing happened.
After that, I tried with the Ubuntu's Startup Disk Creator, in another machine, but it doesn't work.
After that I tried with the Universal USB Installer, and it doesn't work.
At the end, I came to windows, and then I formatted my USB with the diskparter tool, with this metod:
Diskpart is a program available in Windows XP, Vista, 7 and 8.
Press Windows+R
Write cmd and press Return <<< A windows console will appears.
Write diskpart and press Return
It will open a new window, maybe it will ask if you want to execute it like Administrator, and then a new console will appears.
Write: list disk
This command will list every storage device connected to the PC.
Take note of wich is your device, because yo can format your PC's hard drive.
And then write: select disk X (Where X is your USB device)
After that, you need to type the next commands:
clean
create partition primary
format fs=NTFS >>>>> It is slow, or
format fs=NTFS quick >>>> It is fast!
assign
exit
After that, I could use the Universal USB Installer, and I could install Ubuntu 14.04.1