Studio XPS keyboard does not work

Hello.

A few days ago I spilled water on my Dell Studio XPS 1645 and the keyboard stopped working. The backlit works but no keystrokes are recognized When I press the Caps Lock key the light also does not come on. Everything else works and I can use the laptop with a USB keyboard. So I thought that the water damaged the keyboard, purchased a new one but it did not make any difference. The new keyboard also has the backlit on but none of the keys works. I did all the recommended things - unplugged it and removed the battery after the spill, wiped the water, let it dry for a few days, tried the trick with unplugging, holding the power button down for a number of seconds, and restarting, removing the keyboard device and letting Windows to reinstall it. But none of it made any difference.

It appears as if there was a problem with the connector were you connect the keyboard cable or further down on the motherboard. Nothing appears to be damaged but 

Is there a simple way, for non-technician, to check if there is power in the keyboard cable connector? or anything else that I should check?

Thanks.

Witold