I get this message when I try to activate Microsoft Office 2010.  I had to re-install a few times as my windows crashed, so I went back to windows 8 and then 8.1: 

Your installation cannot be activated because you have activated up to the limit of your Multiple Activation Key.  Consult you administrator for further help.

I am a single home user.

Hi

According to my research, first we will have to check with the product key provider to confirm if it is still available.

Then we can do a telephone activation.

1.In the Activation Wizard, select the country/region where you reside and where you plan to use the product.

2.Call the Activation Center .The customer service representative asks you for your installation ID (displayed on your screen) and other relevant information. After your installation ID is verified, you receive a confirmation ID.

3.In the Activation Wizard, type the confirmation ID in the spaces provided at the bottom of the screen, and then press ENTER.

For more information, we can refer to the case:

http://answers.microsoft.com/en-us/office/forum/office_2010-office_install/could-not-activate-office-2010-again/cba1cd14-4697-4139-b275-a94f7cac400a

Regards

It seems that Office 2010 MAK activations has exceeded its activation limits. Please contact your IT admin or your provider to confirm this.

Tony Chen