My arrow keys are reversed

Hello,
I have used Excel for a long time and have never seen this. My arrow keys
have been reversed. Up is down, down is up, left is right and right is left.
Everything else seems normal at this point. This occurred in the middle of
a session for no reaon I can explain.
I have checked Excel Options, Advanced and the direction setting is "down".
I can not find any other settings that would seem to make sense. In all
other programs including this question, the arrow keys act as would be
expected.
Have you seen this before, and how might I reverse, reset, change, correct
or what ever to get the arrow keys back to normal in Excel.
I am using Office Home and Student 2007.
Thanks for the help.