XL2002: Cells Automatically Format with Hijri Date Format When You Type "a-" Before a Number

When you create a new workbook in Excel 2002, and you type an expression of the form a1-x in a cell, where x is any number in the range from 1 to 99, the cell automatically formats with an Arabic date format.

This behavior occurs because Excel 2002 interprets these strings as dates in the Hijri calendar.

To resolve this behavior, you must set a registry value, so that Excel does not interpret such strings as dates in the Hijri calendar. To do this:
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

1. Quit all Microsoft Windows programs, including Microsoft Excel 2002.
2. Click Start, and then click Run.
3. In the Open box, type regedit, and then click OK.
4. Locate and then select the following registry key:
   HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Excel\Options
5. On the Edit menu, click New, and then click DWORD Value.
6. Type xl9_hijri, and then press ENTER.
7. On the Edit menu, click Modify.
8. Type 1, and then click OK.
9. On the Registry menu, click Exit.

When you restart Excel 2002 after you set this registry key, the program will no longer interpret these strings as Hijri dates. When this key is not present, Excel functions as if the key were set to 0 and automatically interpret the entered values as Hijri dates.