I have a laptop Del latitude 620. I have had no problems (with this) for 5 yrs. Recently I unplugged the cord and the screen flickered then went almost completely black. I know how to change the power options. I changed the settings for "when unplugged" to always on, still same issue. (I would guess screen power 5% barely can make out that anything is still there.)
Computer screen completely fine while plugged in. No other problems while screen is out.
Please help?

Thank you. I will definitely check it out. BTW it suddenly stopped and has been fine for about a week now.