Edit: here's the way to do it, source here:
Make sure you have opened all the Office products at least once in order to create a registry key. Under HKEY_CURRENT_USER\Software\Microsoft\Office\12.0 then select your product (let's take Word, for example) and change the WordName key to take out the non-commercial use tag. Go to Edit > Permissions, click on Advanced, uncheck "Inherit from parent...", select copy, and remove the "Full Control" ability from administrators and the user you're logged in as. Click OK until you're back to the main form and do the same for PowerPoint, Excel, and OneNote.