I am posting this little tutorial on how to remove the keyboard from a current Lenovo ThinkPad (in my case it's a W510 Thinkpad) because the first time I tried this, I totally failed. Removing the screws on the back of the machine is the easiest part, but right after that I simply could not get the keyboard off, even I closely followed Lenovos official guide which says your supposed to "push" the keyboard gently with two hands towards the screen. I searched the web for hours checking each tutorial and video I could find. Eventually, I found a side-note in some forum where a guy indirectly hinted to a different way. And here it comes (I took some pictures for illustration):
Turn your Thinkpad so that it lays on the closed screen and look for the screws that have a little keyboard icon. Remove those screws. Note that you may have to remove the RAM plating first which covers an additional screw for the keyboard.
Now turn over the ThinkPad again and open the screen. On the lower end of the keyboard you will notice tha the frame of the keyboard has little gaps. Find these gaps. There is one right below the arrow keys on the right hand side and one below the left alt-key. The pictures to the right shall help you understand what I mean
Now get a screwdriver and gently lever off the Keyboard by gently twisting the screwdriver on the opening. You will notice how easily the keyboars will come off. From there on you can handle the rest.