My laptop goes to black screen after the Dell logo. Support Assistant says there are no hardware issue. I suspect a Windows issue and created a bootable USB drive. However, all instructions I see say change the from UEFI to Legacy in order to set the laptop to boot to the USB, and that option is not available to me in BIOS. I see UEFI, I hot enter and no other option appears. Any thoughts/workarounds are welcome.