Workbooks won't open in Excel 2003 XP from Explorer when they are clicked on. Worked fine until a couple of months ago when something in excel was corrupted. I have reinstalled Office XP and the updates - Excel will open, but the workbook doesn't show up. I have to use the "open" command from inside excel to bring up the workbook. Word documents open just fine from Explorer.

Any ideas how to get this to work again?