I have a broken laptop, the screen does not work. I have an external monitor attached. Will it be problem to upgrade to windows 7? Does the laptop screen absolutely need to work for upgrade?
As long as you do the keyboard tango (pressing the right combination of keys to activate the external screen), usually during the splash screen process, you will be fine on the external monitor.
And on some laptops, you don't even need to do this, but your mileage may vary.