Is this a player connected to a TV or an actual Roku TV? All players (and I think all TVs) have a reset button. Find it and with the power connected press and hold it for 30 seconds. You may need something like a paperclip to access the button through the pinhole. It should restart and be back at the "Let's get started" screen.
How to system restart or factory reset your Roku streaming device | Official Roku Support
Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution."
If you appreciate my answer, maybe give me a Kudo.
I am not a Roku employee.