How to view Advanced Boot Options on an external monitor?

Basically, I'm using a lenovo L420 and the screen is broken. I've connected the computer to a couple old monitors i have and it works, however, i cant view the Advanced Boot Options from the monitor and it only displays any image once I've pressed enter and windows has booted up. I just want to factory reset my computer in order to wipe the (c:) drive.

I'm computer retarded, can anyone help?

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