So there are many problems which will cause issues of the screen.
- Try Fn + F5 or something like that
- Remove battery, unplug power, hold power button for 60 seconds, turn on computer with power plug only, then shutdown, add battery and restart
3. Magnetic On/Off Switch to detect of Close/Open Lid
- Your magnet switch is fubar some how. Open up the speaker cover and see if your lid actuator switch that come in contact with the magnet on your lid cover is stuck or not (find where the magnet is in the back of the front lid cover, trace where the magnet area actually touches the base of the computer and you will find the switch)
- Workaround, start windows with lid at 30 degree angle
- You need to replace either Inverter, Blacklight, or everything. =)