Second monitor black screen, VGA output problem?

Hello guys, need some help here

Laptop: Sony VGN-AR38G;
Video card: Nvidia GeForce Go 7600 GT;
2nd Monitor: LCD TV (plug and play, connected to laptop via VGA cable).
Problem: extended desktop shows no image only black screen.

Self diagnose:
TV and VGA cable are both functioning, because I unplugged the VGA from AR38G and switched it onto another laptop, and the TV displayed the extended desktop perfectly.

So the problem should be within AR38G, right?

All the drivers are up to date, and there hasn't been any new installations. (AR38G+TV worked fine until a week ago, then I shut down all equipments for a trip, when I turned them back on, black screen on extended display)

Could this be caused by any power input/output problems? Does the VGA consume any power (5V, is it)?

My laptop has been acting strange lately, say I switched off the lamp, and the speaker will go dead, then I'll have to unplug and plug-in the audio cable connecting the speaker and the laptop to resolve it. Since the lamp and the laptop share the same extension board, could it be some power problem disturbing the internal DC of the laptop?

Is it possible that the laptop isn't outputting enough voltage to the VGA outlet, so even if there is a signal, the TV is not displaying it?
Also, I tried the S-video cable, after connecting the TV and the laptop, on control panel/display the TV is recognised as the 3rd monitor, but nothing is displayed on TV, says no signal.

Many thanks in advance.
 
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