Laptop screen won't turn on without the AC adapter(battery has 100% power) help?

[curtains]

hey can anyone help me I have a dell inspiron 8600, but the screen won't turn on without the AC adapter pluged in, the battery is fully charged... the thing is that I can turn it on with the AC adapter then unplug it and it'll still work it just needs to be started with the AC adapter.

When i start it without the AC adapter the whole computer starts up makes the windows noise so i know it loads up

i've try updating the bio's and the drivers none have fixed the issue, i've had a look throught the bio's and that has nothing to do with it.

Any help would be great

 

[AdmnPower]

sounds like a problem with the power inverter for the lcd backlight is having issues and is pulling more power than it is supposed to which would be why it won't come on when you power up when you're on battery and will come on when it's plugged in. I'm not sure exactly what you'd do about this though.