Lost data in Excel 2008!! Please help!

I have just done something incredibly stupid and hope that someone may have a solution. I have been working on a spreadsheet for the past 4 hours and saving regularly. As I saved, the following message popped up:

"Some content in Name.xls may not be saved because it is not compatible with the Excel 97-2004 Workbook (.xls) file format. Do you still want to save the workbook in this format?

To save the workbook in a new format and preserve all content, click No, and then on the Format pop-up menu, click Excel Workbook (.xlsx). To save the workbook in the current format and remove all incompatible content, click Yes."

Somehow I managed to not read the popup properly and just went ahead and saved (clicked "yes"). I then closed the spreadsheet and now all the work from the past 4 hours is gone.

Is there any way to recover it?

Thanks so much!

 

Re: Lost data in Excel 2008!! Please help!

I am scratching my head as to why this happened, i.e. what was the compatibility issue? Yesterday I was saving regularly (with those same popups), as I was today. All I have been doing is entering data and pasting data from another file. Seems that yesterday everything saved fine and today, not a single item saved.