Why does screen flicker on then go black?

On my Macbook Pro A1150, screen suddenly went blank / black. Power off and on, and the screen flickers on, then goes blank. Otherwise, powers up successfully. What do I need to replace or fix? How?

OK, it took me six days to find an external monitor. I had tried on my flat-panel TV, but received error, "invalid format." Now, on an old flat-panel Dell monitor, two part answer, but bottom line is, external screen SEEMS TO WORK. However, in Mac mode, comes up obviously in wrong video mode and no way (none apparent to me) to adjust that. In Windows mode (Boot Camp), Windows XP comes up can read screen fine, then switches and error says "cannot read this mode" (paraphrase, forget the quote).

So, two questions now. 1) Must be my problem is NOT the logic board, so is it more likely the Mac laptop screen, or that "converter" card? 2) Maybe I just use an external monitor, but how do I change video modes when can't get it to come all the way up to place where can change? Thanks for advice.