Suddenly my Excel 2003 started acting "wierd". Numbers entered on a NEW
spreadsheet as numbers (1,2,3.45, etc) are being treated as "characters"
rather than numbers. As a result, they don't calculate correctly, format
correctly or justify correctly.

It's as if I entered '123 rather than 123. Formating these cells results in
"1 23" rather than "1.23". Naturally =SUM() doesn't work either. Nothing
I've tried seems to make any difference.

I've uninstalled an reinstalled Excel 2003 several times. I even
reinstalled Excel 2002 and it behaves the same way. Must be some "global
setting" that's gotten whacked but I'm at a loss to know what.