Dell Studio 1555 keyboard stops working

Yesterday, my wife called in slight panic – home laptop Dell Studio 1555 keyboard suddenly stopped working.
This is pretty unpleasant, because I use this computer for developing my projects.

Googling brought me a solution in the second search result “dell studio 1555 keyboard not working“.
It sounds funny, but actually it works:

You need to shut down your Studio 15 laptop. Unplug power cord and take out the battery. Then hold down the Power on button for approx 30 secs. Once done replace the battery and power cord and start up as normal. The problem should now be solved.

This actually worked for me as described.