Forgot password AND display is broken....

I've got an hp Pavillion dv2500 with windows vista on it. The primary display is cracked and nothing can be seen on the screen. If I boot it and press fn f4 to switch to an external display, it will not switch until I reach the login screen. I changed the password to something easy for my little sisters to remember, but now I can't remember it. All the ways I've seen for resetting a vista password require you to create a bootable usb or cd and then tell BIOS to boot from the disk. I am unable to do this because I cannot see what's on the screen until I get to the login screen. If there is some way to switch to external display while in a boot menu or BIOS, then I could probably fix it, but I haven't been able to figure out any keystroke combination to do that so far. So my question is...anyone know of how to switch to an external display while the system is booting? or anyone know how to reset a password without adjusting stuff in BIOS?

Welcome
This idea may help
To make sure your laptop goes to the external monitor, most laptops will have a function-fx key combo to toggle through the 3 presentation video modes (laptop only, external only, laptop and external). Most laptops I have seen use a Fn-F4 or something similar. It is the key with the monitor inside of a monitor icon.

Ck your manual or get it on line if above does not work