My installation of Kubuntu 16.04 has become unusable after trying to plug in an external monitor - it now renders a black screen every time I log in - so I've decided to just reformat and install Ubuntu (laptop is a Lenovo ThinkPad X1 carbon).
I am trying to install Ubuntu from a usb drive, and after trying 3 different USB drives, 3 separate downloads of Ubuntu (2 of 16.04 and 1 of 14.04), and 3 different USB creators, I always get error messages when I try to boot from the drives like this:
Loading Bootlogo
bootlogo: invalid file format
Error setting up gfxboot
boot:
And this error screen:
I tried a solution from another question that said to type 'help' at the boot prompt and then press enter, and this either gives me the message "uncompression error --system halted" or "could not allocate memory" and I have to hold the power button to switch the laptop off.
I am able to get into the root shell by holding down shift during boot up and entering the GRUB options, but I have no idea what to try. At this point I just want the laptop to work, I don't care about losing all my data.