A few days ago I received Office 2010 from work.

I installed it with the provided product key, and tried to activate it:

Unfortunately, the product key has been already activated for the maximum number of times permitted.

So I asked for a new key, I received it and I tried to change the key

After several researches, I couldn’t find an option to change this key.

I finally tried to repair the installation, so I start the office installer

and  the wanted option was here :

Choose “Enter a product key” then click on Continue

Enter your product key and click on “Continue”.

Then you cant choose if you want to install additional office options

Now it’s activated !