[AccessD] Linked Table - Excel Spreadsheet

I have a customer who has a database with a table linking to an Excel
Spreadsheet. This morning (Monday morning blues) they are unable to access
the data. Access gives an error message saying that the external table is
not in the correct format. When I tried opening the spreadsheet with Excel,
the file is not in the correct format.

The customer says that the only problem they have had is running out of
space on the C: Drive - could this corrupt the Excel file?

Are there any utilities available to repair an Excel file? What steps do I
need to take to retrieve the data?

The customer promises to start taking backups from now on. I need to recover
their data. Can someone on this wonderful list help make me look good in the
customers eyes????

Gary Lockett
Key Solutions
Port Elizabeth
South Africa