Excel 2007

I am not a tech guy, but I understand enough to be dangerous. I have been working with some excel workbooks and saving to 2003 format for a client. Now, when I try to click on the file, excel opens in only a blue screen, with no real commands other than zoom and view choices. No way to close it except with task manager and resizing doesnt bring back the spreadsheet. What did I do, and what do I do to restore the file? Thanks, jim