If you ever need to change the License Key on a Windows Server 2008 box that you don't have RDP or an IP KVM for, there's a CLI method which works remotely.
- If you want to remove all installed license keys
This is useful remove licenses used for testing purposes, before handing a server over to a client who is going to use their own licenses.
- Add new the license key
slmgr. vbs -ipk <license key>
- Activate Windows
- Check to make sure the activation succeeded