Hello, I'm using excel 2003. Can I open an Excel 2007 file using Excel 2003? Is there a way to convert?

Yes if you have a legal copy of excel 2003. Microsoft has a compatibility pack so you can read xlsx files.

http://www.microsoft.com/downloads/details.aspx?Fa...

Yes, download the free compatibility pack directly from Microsoft.

Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats

Brief Description

Open, edit, and save documents, workbooks, and presentations in the file formats new to Microsoft Office Word, Excel, and PowerPoint 2007.

For those that have older Office products installed, the Compatibility Pack is located at the following site:

http://office.microsoft.com/en-us/products/HA10168...

http://www.microsoft.com/downloads/details.aspx?Fa...

Note: If you use Microsoft Word 2000 or Microsoft Word 2002 to read or write documents containing complex scripts, please see http://support.microsoft.com/kb/925451 for information to enable Word 2007 documents to be displayed correctly in your version of Word.