Hi,
You may get this error if the product key has been used. Please make sure the Product key has not been used yet.
If the key has been used, please refer to
www.office.com/myaccount, sign in with your Microsoft Account to install or re-install your Office.
As for the error the account is not valid, you can refer to this kb below:
http://support.microsoft.com/kb/2412085/en-us
Look for the error message which matches your scenario and find the solution.
If the error is as below:
This doesn't look like a valid user ID. Make sure you typed the user ID assigned to you by your organization. It usually looks like
someone@example.com or
someone@example.onmicrosoft.com.
You may need to read this kb:
http://support.microsoft.com/kb/2844931/en-us
If you have further more questions, please contact
www.support.microsoft.com/contactus
Regards,
Melon Chen
TechNet Community Support
