Directional Pad not working after rain

Archived from groups: comp.sys.handhelds (More info?)

Okay, last fall I left my IPAQ 4150 out in the rain ... I figured it
would be shot, but to my surprise it worked fine! Except for the
directional pad. It wont go down. The up, left & right work, just no
going down. It is very frustrating because it's what you use most for
scolling web pages or scrolling down on books.

I looked at opening the back and seeing if there might be rust or
something at the pad - but I don't know what type of screwdriver I
need to open the back.
OR is there a way to reconfigure the directional pad and make the left
or right behave as the down button?

Any help would be appreciated.