macbook 2008 - still alive but barely breathing!

A number of problems could result in a dark display. If its backlight is inoperative or dark you should still see a very faint image under a strong light. Do you see anything at all? If so you might be able to fix this by resetting your NVRAM.

Try starting from your original System Install DVD: start the MacBook while holding the c key.

Do you have another Mac? You could use FireWire Target Disk Mode to mount its internal HD for the purposes of repairing it.

Probably the backlight. As the guy above me said--reset the NVRAM and try looking at the screen in very strong light (such as a flourescent desk lamp perhaps). But I personally wouldn't recommend doing anything fancy to it because if you screw it up on accident Apple's less likely to help you (especially with a 2008 MacBook).

The GeniusBar can use an Ethernet cable to boot a blank OS. If the problem persists on the blank OS, Apple will know that it's a hardware problem and you'll have to pay to fix it. Or try doing it yourself I guess. But if it's a software problem just hope to God that there's some way to back up your stuff. Apple might have ways to recovery your documents, photos, etc for you. Anything with software they will do for free. As long as they like you that is 🙂.

I have the same Macbook and a similar problem! I tried to switch it on this morning and it loads to a grey screen with the little white light flickering at the front - before suddenly going black. Did you have any luck fixing it?