Here is our guide on reinstalling Ubuntu with Lambda Stack:
The URL says 18.04 but the links within will take you to the Ubuntu 20.04 install. I also see that you’ve inquired about if Lambda Stack works on 21.10. While most, if not all, should still work on 21.10, we do not support Ubuntu 21.10 so we won’t be able to assist you should you encounter any issues. As such, I’d highly recommend sticking with 20.04.
Please follow the guide to restore the laptop and do reach out should you find that your Tensorbook is still overheating. Also, if you’re wanting to generate a ticket with our support team for quicker responses, please email firstname.lastname@example.org