HP Keyboard are indeed more complicated then regular ones. Regular ones are usually quite easy to pop out and push back. For laptops however, it's different, as you need to know how the mechanism is made underneath.



Here you can find information about how to do that for a HP Keyboard:



Note that the mechanism may be a bit different for your own laptop, but keep in mind that it is based on same idea. You have usually two parts together under the actual key, and a part acting like a spring underneath it.



Knowing how it looks inside may help you, I hope. In general, keep in mind that you want to pop the top part out, not the two inside ones, and that this part is held usually on four corners, as described in the given link. Apply your effort to pop it from a corner. It will require a bit of effort, especially that you have to be careful to not actually break one of the inside parts.



In general, I would not recommend popping out all the keys from a HP Keyboard to clean them. Do it for the really stuck and sticky ones, but it is not as trivial as a regular keyboard, as you can see.