Need to get laptop to display on external monitor when booting
I have a MacBook with a bad display which I am using with an external monitor. I have already replaced the video/isight cable to no avail and I'm not ready to spring for an lcd just yet. The problem with my setup is that I still have the original owner's password active to make changes and I don't know it. When I try to boot to disk to use the PW utility the MB won't display on external. Same for 'option' boot. I can't reinstall because I cant see what I'm doing. Is there a way to force the use of external monitor only?
EDIT:
Update to my comment bellow. I tried unplugging the Video cable and inverter (just in case) and I can boot to 'option' mode. Unfortunately as soon as I insert the Disk and then choose that as the boot option the screen reverts back to stretch mode with the OSx wallpaper. I can't even tell if the disk install/utilities desktop is up. I also tried the 'c' boot option and same thing. I'm stuck with
the previous owner's locked install. I can't even scan for updates!
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