My S letter on laptop keyboard has a habit of not working...

There is probably something under the key that is keeping it from releasing correctly. If you have a spray can of air, you can see if you can get it to release the key by spraying between the keys. Sometimes that will work. Otherwise, you may need to remove the keycap and seeing if you can release the key that way. Very carefully ease a Q-tip under the key and see what comes out. Replace the keycap and test it to see if that fixed it.

I had the same experience with my computer keyboard. For me it was the letter C. I removed the key, it was worn out, I clued to the key a very small piece of paper and now it works.

You likely got something under the switch that's making it act that way. I've broken many keys on my windows laptops over the years from general wear and tear and typing like a mad woman. I also use the keyboard more then the adverage user would, too. You can try removing the key cap and going over it with compressed air or a ?tip. Or, you can break down and get a bluetooth or wired external keyboard.

Mine is number Zero, lol! Maybe something is stuck in it, or you just need to clean your keyboard, or you need to replace it.

I had some trouble with the letter E on my keyboard, but I may be thinking of my previous keyboard because it's fine, now.

I bought a new keyboard last year. I lost the battery cover on my old one. I didn't want my mother to lose the battery to other one while I was up in NJ for the holidays. So I got this one which is a bluetooth one.

I can’t really think of a similar experience I’ve had.