Laptop won't start with external monitor, (can't see boot menu)?

[coopercrueV2]

So I broke the screen on my laptop, the external monitor does not show the boot screen, and if I leave it alone it dosen't do anything, it is on, but i can't see anything. I have tried turning it on, pressing enter and stuff, and it still dosen't work. Any suggestions?

[ze beaver]

Laptops usually don't switch output as soon as you plug an external screen.

There should be either :

a. A dedicated button to switch screens (very unlikely)
b. A Fn key to switch displays (very likely)

If you can't find it, tell me your laptop's model.

[coopercrueV2]

Found it, still won't switch to boot screen. Maybe someone could tell me a key combination to get back to normal windows? (win 7)