If you have a Sony VAIO laptop, you may have the problem that one day you try to to turn it on and nothing happens.  A Google search reveals that this is a fairly common problem with VAIOs.  I have a PCG-V505BX and it happens to my machine about every six months.

Several websites suggest that swapping the RAM will solve the problem, but that did not work for me. Instead, the solution I found is to unplug the system battery, wait a minute, and plug it back in again.  Below you will find some instructions for how to do this.  At some point, I plan on posting pictures that show each step in the instructions, but for now words will have to do:

(1) Remove the (regular, not system) battery from your laptop and unplug the power supply.   It is better if there is no power going to your laptop when you open it.

(2) Remove the keyboard.  The keyboard is typically secured by one screw and some plastic tabs. 

(2a) Remove the screw that secures the keyboard.  Turn the laptop upsidedown and look for a screw near the center.  Take that screw out.   The screw should be about as long as your computer is thick, because the screw has to go all the way through your laptop to secure the keyboard.   If the screw is much shorter than your laptop is thick, it is probably the wrong screw.    

(2b) Turn your laptop right-side-up again, open it, and put your fingernails (or a flathead screwdriver) underneath the top of the keyboard and gently pry upwards.   The keyboard should pop out easily.   If it does not, you probably have some more screws to remove in back.

(3) Now you should be able to see the system battery plain and clear.   Do not try to pry the battery up.   It is not meant to come out like that.  Instead, pull on the two wires that run from the battery.  They will disconnect from wherever they are attached to and reveal a small white connector.   Wait about a minute, and then plug those wires back in where they came from.  

(4)  Replace the keyboard.  You can put the screw back in, or you can just leave the keyboard attached by its plastic tabs so that the battery is easier to access when the problem happens again some months in the future.

Sony VAIO won't power up
Sony VAIO won't power on
Sony VAIO won't turn on
Sony VAIO power problem