Aditya, there are two possibilities that I an think of right now, number one is that your click-wheel needs to be replaced number two that your logic board is not recognizing your click wheel. I f nothing has happened to the iPod I would open it up and take a look at the click-wheel connection. Make sure that the clip that holds the cable to the logic board is engaged, meaning that it is down. Also of course check for any corrosion on the board and the click wheel connector and cable itself. After cleaning and should it still not working, start with the click wheel. Oh, and while you are at it and it is open, change your battery as well. this way you will not have to worry about it for another three years. Good Luck and let us know if this worked.

iPod Classic Click Wheel Replacement