rca_tablet_problem

I have an RCA tablet, the model I don't remember. I originally tried installing Kali linux via usb but was having troubles due to network connections..so I decided to try for Ubuntu instead. The tablet doesn't boot into windows anymore, and when I try to boot from usb through the BIOS it goes straight into uefi shell... like it ignores the usb. I have tried three seperate programs to format the ISO to the usb drive. the BIOS picks up the name of the usb stick but it doesn't boot into it.