Q: Screen went black

My iphone's screen went green, then slowly turned black. I tried a "soft restart" on it but the screen is still completely black. I then plugged my phone into my laptop and opened Itunes, and it is making a noise indicating that it is charging, but I am getting an error along the lines of "iTunes cannot connect because the phone is locked and has a passcode." I am not sure what to do about my passcode, since the screen is black.