If you need a viewer, you can download one here for free.
Microsoft Excel Viewer - for Excel 97, 2000, 2002 and Office Excel 2003, Excel 2007 users
Microsoft Word Viewer - for Word 97, 2000, 2002 and Office Word 2003, Word 2007 users
(This viewer will also open files saved in Rich Text Format (.rtf))
Microsoft PowerPoint Viewer 2007 - for PowerPoint 97, 2000, 2002 and Office PowerPoint 2003, PowerPoint 2007 users
Adobe Reader - for PDF files
Winzip - for zip files