Comment 7 for bug 355054

I notice you have a Dell. Can you try booting with the "reboot=b" boot option to see if it allows you to at least reboot? For help on how to try the reboot=b option do the following, press 'Escape' key at the 3 second pause by Grub bootloader. Then press 'e' (edit) on the kernel entry, followed by 'e' again on the kernel line. Add "reboot=b" (without quotes) to the end of the line and press 'b' to boot. Once you've booted try rebooting to see if it works. If it does, please attach the output of:

sudo dmidecode > dmidecode.log