From time to time, you may need to reinstall Microsoft Office because you purchased a new computer or you're trying to resolve a program error. Or, in Excel 2010 and later, you may need to move between the 32-bit and 64-bit versions. In this article, I'll describe how to download the installation files on demand as well as recover a lost product key for Office.
The instructions that follow are specific to Excel 2007 and later. (I was unable to determine how to download Excel 2003 and earlier from the Microsoft website.) Links are all current as of the date of this article (October 31, 2013), but they are subject to change without notice.