This is caused by moisture. First try and figure out what the source of the moisture is and repair it. Unfortunately, the only thing you can do it take it up. If you have some left over from your installation and it's just a few boards, you can just replace the few boards, otherwise, it all has to come up. If it's been down longer than 3 years, most likely, the click mechanism has changed and it will be impossible to find a box that will match up to what you already have.
