If you ever need to reinstall your Microsoft office 2010 software and don't have the original installation DVD (in case you purchased a compouter with Office preinstalled) you can download your copy here: http://office.microsoft.com/en-us/products/microsoft-office-2010-backup-FX101853122.aspx
If you are looking for a copy of Office 2007 download it here: http://www.microsoft.com/office/backup2007/en-us/default.mspx
You will need your valid product code to start the download.
