Hi,
I have created an excel workbook in Office 2003, and then my system has been updated to Office 2007. While saving the workbook in the new version, and error occured which caused the loss of the file.
When I try to open it now, the following error message appears "Excel cannot open the file 'filename.xlsx' because the file format for the file extension is not valid. Verify that the file has not been corrupted and that the file extension matches the format of the file." (id. 101590).
I tried to repair the file, but the same message appears again, and when I tried to follow MS instruction for this error (http://support.microsoft.com/kb/928979), the only option to save as I have is excel 97-2003, and again it does not work.
Can somebody please help me solving this as the file is really important, and all backup copies have been deleted by mistake.
Thanks