Are you sure that the product key is correct? Sometimes, one hasn't entered the correct digits and/or letters for the simple reason that they may be difficult to read. You are correct that you won't get any assistance from Microsoft, because Office 2007 is out of support. Stefan Blom. Office Apps & Services (Word) MVP since 2005. Answer. The 25 character product key is your proof of ownership of Office. Depending on the type of Office license you bought you may or may not be able to transfer it to a new computer. If you bought a boxed CD or '2-computer' or '3-computer' or "FPP" type license you can transfer it. If you bought a "Product Key Card" or '1-computer' license Go to the Microsoft Website. Go to Services and Subscriptions. Scroll to find the Key. Copy the Key to transfer to your new installation. Don’t lose your key. Your Microsoft Office Product Key is a series of 25 letters and numbers that must be entered when software is activated on your devices. This Key certifies that the software is an faXCt.