Question:

So you bought a new copy of Office 2007 Professional.  How many computers can you install it on?

The license agreement contains the following:

1. OVERVIEW. These license terms permit installation and use of one copy of the software on one device, along with other rights, all as described below.
2. INSTALLATION AND USE RIGHTS. Before you use the software under a license, you must assign that license to one device. That device is the "licensed device."  A hardware partition or blade is considered to be a separate device.
a. Licensed Device. You may install and use one copy of the software on the licensed device.
b. Portable Device. You may install another copy on a portable device for use by the single primary user of the licensed device.
c. Separation of Components. The components of the software are licensed as a single unit.  You may not separate the components and install them on different devices.

Answer:

You can install it on your desktop, and your laptop, as long as you use both machines.