I have just purchased a laptop with ubuntu 12.04 LTS on it. i am not very familar with ubunto. never used it before. i locked myself out of the administrator account and didnt know the password. i then had to shutdown the machine in a guest account. when i came to restart the computer it came up with the No INIT found try passing to bootarg. I have tried to load from a livecd created from unetbootin on a usb stick (4gb) (windows based selection)and i have switched boot device to boot from usb. but it does nothing i just get a blank black screen. can anyone help me please.