How to add a product key to an evaluation version of System Center 2012 Operations Manager

To set the product key, use the Set-SCOMLicense cmdlet in PowerShell. To use the Set-SCOMLicense cmdlet you need to use elevated permissions. (Run as Administrator).

1. Open PowerShell as an Administrator
2. Load the OperationsManager Module
         import-module operationsmanager

3. Connect to your ManagementGroup
        SCOMManagementGroupConnection

4. Use Set-SCOMLicense -ProductId "yourlicensekey"
5. To check if changes were executed run Get-SCOMManagementGroup | ft skuforlicense, version, timeofexpiration –a

Note:
This may require a reboot after running in order to register correctly.

Hope that this post was helpful.