Hi Richard,

I'm sorry to hear that you're having trouble with your Excel workbook. It sounds like a frustrating situation, but I'll do my best to help you out.

Based on the information you've provided, it seems like the issue may be related to compatibility between Excel 2000 and Excel 2003. While the two versions are similar, there may be some differences in how they handle certain features or functions.

Here are a few things you could try to resolve the issue:

1. Save the workbook in a different file format: As you mentioned, saving the workbook in Excel 97 format resulted in an error message. However, you could try saving it in a different format, such as Excel 2003 XML or CSV. This may help to eliminate any compatibility issues between the two versions of Excel.
2. Remove unnecessary formatting: You mentioned that the workbook has a lot of formatting, which may be contributing to the issue. Try removing any unnecessary formatting, such as cell borders or background colors, and see if that helps.
3. Use the "Detect and Repair" featu Excel has a built-in "Detect and Repair" feature that can help to fix any issues with the program. To access this feature, go to the "Help" menu and select "Detect and Repair". Follow the prompts to complete the repair process.
4. Check for updates: Make sure that both Excel 2000 and Excel 2003 are fully updated with the latest patches and service packs. This may help to resolve any compatibility issues.
5. Try using a different computer: If possible, try opening the workbook on a different computer with Excel 2003 installed. This will help to determine if the issue is specific to your computer or if it's a more general compatibility issue.

I hope these suggestions help you to resolve the issue. Let me know if you have any other questions or if there's anything else I can do to assist you.