This key sequence will vary from manufacturer to manufacturer.
Disclaimer: I just tested the method in the post with my laptop and am not sure whether it works with one specific model (although it seems work for some others according to the comments).
The method in the post is just one example solution.
But when you get done adding that extra memory, it is important to make sure your computer recognizes the upgrade.
You can check the memory status by entering the computer's BIOS. Watch for a message that says "press X to enter setup." The key sequence used to enter the BIOS varies from manufacturer to manufacturer.
Turn off the computer and remove the case if the additional memory is not reflected in the computer's BIOS.