One thing you can try is to carefully remove the shift key from the keyboard. You will see one or two clips and possibly a metal clip or something. I suggest taking a picture before you remove any clips. Then check to see if the rubber underneath is intact and cleared from debris. I recommend powering off the CB and use a Q-tip with rubbing alcohol to clean the area. It could be sticky or something is preventing the button from pressing down. For a Dell CB, I had to put a piece of folded paper because a student removed the rubber underneath the key. I would see if it exists and if that's not the case, see if the rubber can be moved. If so, carefully move it and see if you can press the button underneath and see if that works.