Q: Screen gone very dark even after restart

Hi, I left my iBook restarting & when I got back the srceen has gone very dark.
As you can see I can just see enough to type but it's hard to see the browser navigation & menus.

I need to use Photoshop & this dark screen won't do
I restarted & same dark screen.

I'm wondering if it's worth trying to connect a screen via s-video?
I once tried to connect a screen a friend offered to lend  me & after a while Apple told me my Mac wasn't made to use an external screen but could only connect to a projector. I did once manage to connect it succesfully to a very large flatsceen in a lecture hall via the video connector using S-video.

If this built in screen dies will I still be able to see one connected via S-video?

Does anyone think it worth while trying to buy a screen with S-video connection?
Or is this the beggining of the end & I should back up quick & fundraise for a new Mac.

I have replaced the hardrive maybe 2 years ago so that should be OK.

Any help much appreciated,