First, turn of secure boot if it is enabled, you might have better luck with bios (legacy) mode.
Dell only supports Ubuntu 12.04 on this laptop, there are quite a few posts online about upgrades to 14.04lts destroying the install.
You might try searching Dell's Linux forum for a solution.
http://en.community.dell.com/support-for...-os/f/3525
Dell only supports Ubuntu 12.04 on this laptop, there are quite a few posts online about upgrades to 14.04lts destroying the install.
You might try searching Dell's Linux forum for a solution.
http://en.community.dell.com/support-for...-os/f/3525