Remove the Existing Product Key from Server
slmgr.vbs -ckms
Enter the New Product key in to Server 2008
slmgr.vbs -ipk xxxx-xxxx-xxxx-xxxx
Note: Replace the xxxx by given code
If the product code is correct this should return a dialog box indicating success, otherwise it fails. Once you have specified the correct product code it's time to register by issuing command:
slmgr.vbs -ato
A successful activation will return a success dialog box and a failure will indicate as such.
