[abhinavjoshua]

Why does my extension board LED lit even when I turn off the power from the mains?

I have attached some pictures to make things simpler and clear.
Here are some pics in order. Kindy go through them. The information is given in the picture itself!

This is the wall outlet where extension board is connected.


This is the extension board with the cord of the speaker connected to it. The switches are turned off, but the LED is still glowing...
http://www.freeimagehosting.net/nl7ln

This is the sub woofer where both the input and output RCA jacks are connected.
http://www.freeimagehosting.net/17mk6

But as soon as I disconnect the RCA jacks, LED light turns off. (See pic)
http://www.freeimagehosting.net/5gm3w

This is the wall outlet where my PC is connected. (There must be something wrong with the "PC thing" because the the LED turns off when I disconnect the RCA jacks from the sub woofer whereas the audio input is coming from the PC itself!)
http://www.freeimagehosting.net/v59up

These are the connections inside the wall outlet of my PC.
http://www.freeimagehosting.net/jsynu

Kindly go through all pictures and let me know if you need more information on anything.
What is the source of the problem? A ground?

P.S. There is no grounding in my home!

[andrew79]

because an led draws a very small amount of power, it's probably just the capacitors in the board discharging through it.

[freedomlives]

Does the extension strip LED stay lit when it is unplugged from the mains?

Given the way your outlet box is wired, even when the switch going to one outlet is "off", the hot leg of that conductor is still hot. So current could be flowing into the outlet strip, through the subwoofer and out through the connection to the computer into the neutral conductor there. It isn't a good thing if this happening either, since it might indicate a fault in the insulation of the subwoofer.

Also, it isn't a good idea to connect a grounding wire to a faucet, etc. especially since the piping going to the faucet may not be providing a good path (i.e. if there is plastic piping somewhere in the system) and could therefore provide a risk of shock.