Office 07-Office 03

Have an odd problem on an XP Pro machine

It has a full version of Office 07 installed on it but when you try to open an excell 2003 xls file saved from a different computer it opens blank, not blank cells, just excel with no workbooks.

Tried to do a repair and it did not help.
If you save a excel doc in 2003 format on the computer it will open fine.

Thanks for help