I use Office 2003 as my office software. But I have a problem when I get file created by new Office Product (example file from Office 2007). Output file from Office 2007 is a *.docx and *.xlsx for extension Word and Excel Program. Because my Office 2003 can not open this *.docx and *.xlsx file. I have a problem when exchanging files between previous release of Microsoft Office.
If you use OpenOffice, you can solve this problem. Because OpenOffice can read and save docx and xlsx extension file. But if you have old Microsoft Office product, you can open this new extension file with install Microsoft Office Compatibility Pack. When you finished install this program, you can read file saved in Microsoft Office 2007 with your old Microsoft Office (ex. Office 2003). So, exchanging files between previous Microsoft Office is not problem again.
You can download Microsoft Office Compatibility Pack in here.