Thanks for posting. Apologies that your system is not performing as expected.
Have you done any diagnostics testing on the computer?
Does the screen work with an external monitor attached?
Please perform a systems diagnostics by pressing F12 at startup or by running Dell Support Assist. Make a note of any errors and post back.
Here is some information from the Dell knowledge base you may find helpful:
Ubuntu 18.04 does not seem to be available for download yet. I will try 17.10 as soon as possible. I hope it works!
Extremely unacceptable behavior by Dell. The least they could do is support their flagship device for a few years.