I turned on my laptop today with it connected to the powers supply and it has the Windows's loading bit just before it loads up your desktop then the screen just stays black. The laptop make is a emachine and not sure how to fix it need to get my work done for Monday on it.
Had a similar problem with mine a while back. The backlight was bust. Depending on the model the spare can be a couple of quid (e.g. Hewlett Packard (I think the geezer said) who design, source & build from scratch but cost more to buy) - right through to a hundred quid (e.g. Gateway who design around somebody elses blueprint, buy-in units of parts then assemble them but sell cheaply)
Luck of the draw.