Since the Enterprise customers are allowed to use a Multiple Activation Key (MAK) with Key Management Service (KMS) to activate Microsoft Windows Vista Business and Enterprise editions inside the organizations, it is not worth to install KMS for less than 25 clients. To activate an instance of enterprise Vista edition by avoiding the KMS requirement is now very straightforward with the procedure introduced by Microsoft.
The typical Internet activation for the first time will give the below error message if the product is installed with a MAK.
Activation Error: Code 0x8007232b
DNS Name does not exist
With reference to the error you can find the KB article at http://support.microsoft.com/kb/929826 for detailed infomation.
You must do the activation within the 30days of grace period of product activation with having legitimacy of doing so. Below step provides necessary instruction as per the Microsoft Partner Portal.
Using the CMD prompt: Click Start > Programs > Accessories, and then right-click CMD Prompt (run as Administrator). In the CMD prompt, run Slmgr.vbs –ipk xxxxx-xxxxx-xxxxx-xxxxx-xxxxx where the key string is the MAK assigned to your account in the Partner Membership Center (PMC).
Upon the successful completion restart would require to see the activation status update in System information panel.