There is a tiny button on the motherboard, top right corner. I’m trying to find a good picture of it. You could use it to get into the BIOS, and then do as @Scott_H suggested.
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The black dot in the middle of the button is what you click. Be careful when pressing it, you don’t want to damage it or any tiny parts nearby. You should not to use any very pointy object to push it, e.g. I would not use a pen point. Maybe the blunt back of a pen. If you are on the black dot, the button should not take much force to click.