Can you download the latest version of Microsoft Office for free if you have an older version already installed on your computer or do you have to pay for it?

The current version is Microsoft Office 2007, which is not available for free download. You can purchase and upgrade version of 2007 which is moderately inexpensive compared to the full non-upgrade version of Office.

You can also pay and download from Microsoft, Office 2007

Lastly, the public beta for Office 2010 is also available for free download as long as you have a valid hotmail of live.com email address.