If you are needing to change the Product Key in Microsoft Office 2013 Home and Business and don’t want to go to the trouble of uninstalling and reinstalling Office 2013 the following commands should assist in changing the product key.  These commands are useful when the “Enter a Product Key” option in Programs & Features are not available / working or you’d like to do it from a command prompt.

Step 1. Open a Command Prompt

For Windows 7 – Click on Start and type CMD in the search box. Press Enter.

For Windows 8 and higher – Press your Windows key and type CMD.  Press Enter.

Step 2. Enter the following Command

The command you will enter to change your Office 2013 key will depend on the version of office you are using along with the version of Windows.

For Windows 32 Bit with Office 2013 32 Bit installed

cscript "C:\Program Files\Microsoft Office\Office15\OSPP.VBS" /inpkey:yournewproductkey

For Windows 64 Bit with Office 2013 32 Bit installed

cscript "C:\Program Files (x86)\Microsoft Office\Office15\OSPP.VBS" /inpkey:yournewproductkey

For Windows 64 Bit with Office 2013 64 Bit installed

cscript "C:\Program Files\Microsoft Office\Office15\OSPP.VBS" /inpkey:yournewproductkey

Conclusion

The above commands should work in most instances to change your Office 2013 Home and Business Product Key.  Other methods include right clicking on changing the program from Programs and Features (sometimes this isn’t available) and uninstalling and reinstalling Office 2013.