In most cases, you'll need your product key to activate Office 2010. Need help finding your product key?
Activate Office 2010 online
Click File > Help > Activate Product Key.
If you don't see an Activate Product Key button, your software is already activated, and you don't need to do anything.
Follow the steps in the Activation Wizard.
If you're activating over the Internet and have a slow connection, you might want to activate by phone.
Activate Office 2010 by phone
In the Activation Wizard, choose I want to activate the software by telephone .
Select your country or region to see the phone number for your area.
Microsoft Text Telephone (TT/TTY) services are available for individuals who are deaf or hard of hearing. In the United States, using a TT/TTY modem, dial (800) 718-1599. From outside the United States, using a TT/TTY modem, dial (716) 871-6859. TT/TTY service is only available in English.
When you call the Activation Center, you'll be asked to provide the installation ID (displayed on your screen) and other relevant information. After your installation ID is verified, you'll receive a confirmation ID.
In the Activation Wizard, type the confirmation ID in the spaces provided at the bottom of the screen, and then press the Enter key.
Tip: If you still can't activate Office, call the activation number, but don't enter anything or say anything. You'll be transferred to someone who can help you.
Activate Office 2010 on a different or restored computer
Your Office 2010 license allows you to reinstall Office on the same computer, and some licenses allow you to activate Office on more than one computer. But if you try activating Office and you get a message that you have installed it too many times, use the telephone option in the Activation Wizard to contact a support technician. To learn more about what the license terms allow, read the Microsoft Software License Terms for your Office product.
What happens if you don't activate Office 2010
If you don't activate your software, eventually Office 2010 switches to Reduced Functionality mode where it lets you open files to view them but not edit them. You can still activate by going to File > Help > Activate Product Key. In the Activation Wizard, choose the option for activating by telephone, and when you call the activation number, but do not enter anything or say anything. You'll be transferred to someone who can help you.