Bones_Malone
Try to find out, how you have to set up the bios of your Dell XPS, so that it can boot from USB.
This seems to be an issue with your Notebook and not with Batocera (because as you said, on other machines you can boot from usb).
Otherwise i looked up the technical details for this notebook and it has a NVIDIA GeForce GT 555M graphics card.
You should check, if this card is supported by standard Batocera or legacy-version.
See here: https://wiki.batocera.org/doku.php?id=supported_hardware#nvidia_drivers
You could also have a look in the bios, if you can disable the nvidia GPU, so that it uses intel iGPU instead (if possible).