This is the information you need - straight from the FAQ page attached to
the Trial Download page.
--
Terry Farrell - MS Word MVP
You can convert from the trial software to a full-version either before or
after your trial period ends.
Before the trial period ends:
You will start receiving expiration reminder messages indicating the date
when the trial will expire. At this point, you can convert to the full
product in two ways:
In any of the expiration reminder messages, click Convert, and then follow
the steps in the conversion process, below.
At any time during the trial period (or even after the trial has expired),
you can open any of the Microsoft Office System products, and in the Help
menu: click "Activate your software".
After the trial period expires:
The software goes into reduced functionality mode. Some of the limitations
of reduced functionality mode include the following:
You can not create any new files.
You can view existing files, but you can not modify them.
You can print files, but you can not save them.
You can convert into a full-use version of the product by following these
steps:
The Conversion Process:
Follow these steps to convert your Microsoft Office System trial product to
perpetual use with no uninstall or reinstall necessary.
Step 1: Get Perpetual Product Key and Start Conversion Process
Obtain the Microsoft Office System product at any retailer or online to get
a perpetual product key. After you have obtained your perpetual product you
have two Options to start the conversion process.
Option 1:
In any of the Microsoft Office trial expiration reminder messages, click
Convert.
Option 2:
In either Access, Excel, PowerPoint, or Word, click the Microsoft Office
icon ,click Program Name Options, click Resources, and click Activate.In
either InfoPath, OneNote, Outlook, Publisher, Project, or Visio, click the
Help menu, click Activate Product, and follow the instructions in the
Activation Wizard.
Note: To avoid uninstalling the trial if you obtain the full product version
at retail, the full product version should be the same version and language
as the trial software. For example, if the trial software is 2007 Microsoft
Office Home and Student English, the full product version should be 2007
Microsoft Office Home and Student English as well. If the full product
version is a different language version, you will have to uninstall the
trial and manually install the full product version.
Step 2: Convert Your Trial Through Set-Up Wizard
In the Setup dialog box, click Enter Product Key if you have purchased a
perpetual product key from a retailer or click Buy Online Key if you do not
have a perpetual product key and would like to purchase it online.
Note: When converting to a full product, you are encouraged to compare
prices between our authorized resellers both through retail and online.
Prices may vary. If you choose to obtain the product online, you will be
routed to the Microsoft Web site and the Microsoft eCommerce vendor to
obtain a perpetual product key. You will then be returned to Office Setup.
Step 3: Enter the Product Key
Enter the product key shown on the packaging of the perpetual product
obtained at retail, or the product key that you obtained online. Click
Continue.
Step 4: Accept Microsoft Software License Terms to Install
You will then see the Microsoft Software License Terms (MSLT). Accept this
agreement to use the software by selecting "I accept the terms in the
License Agreement" and click Next.
After you accept the MSLT, an alert window will open saying that your
product is being updated. Another message will open once the software has
been set up successfully.
After launching the full version for the first time: You will be prompted to
activate it. Unlike the trial activation, during activation of the full
version, you will have the option to activate the software either over the
Internet or by telephone. The default option is to activate the software
over the Internet. Once that is done, the trial is converted to perpetual
use with no uninstall or reinstall necessary.
