However, losing that 25-character code is a common headache. This guide covers how to find your key and the exact steps to activate your software. What is the Microsoft Office 2010 Product Key?

If you purchased and downloaded Office 2010 online directly from Microsoft or a digital retailer, search your inbox for "Microsoft Office" or "Digital Receipt."

The product key is a unique 25-character alphanumeric code used to "unlock" the software. It proves that you have a legitimate license and prevents software piracy. It typically looks like this: XXXXX-XXXXX-XXXXX-XXXXX-XXXXX Where to Find Your Product Key

If Office 2010 is already on your computer but is in "Trial" or "Unlicensed" mode: Open any Office program (like or Excel ). Click the File tab in the top-left corner. Select Help from the left-hand sidebar.

When you first run the installer (from a disc or a downloaded file), the very first screen will usually ask for the key. Type the into the text box.