If you can hear clicking, I think that the click wheel is probably working. The display has probably failed. You can get a replacement fairly cheaply on ebay. Be very careful when disassembling,the ribbon cable that connects the display to the main board is very fragle, and has probably gotten wet. I would use some isopropyl alcohol on the connector and cable before taking it apart. I have seen the gold traces peel off the ribbon cable when disconnecting it, rendering the display useless, so be cautious!