Laptop Display locked to VGA Port

Hi, Im having problem with my laptop display not coming up after boot-up. I know its not a hardware problem because other windows partitions are display fine.

The problem occured after I had an external monitor plugged into the VGA Port and had display setup to extend onto it. I turned off laptop while display extended, then unplugged screen. Later I started laptop by itself, the initial loading screens come up but it goes black as soon as it gets past windows loading logo. Ive tried plugging screen back in, as well as using function key (which does work during startup) but no good.

If people have hit this problem before, or know of a way to restore display setup to default, it would be greatly appreciated.

Leon