1) Stop the service on the old machine (Spotlight Diagnostic Server service).
2) Then backup Agent directory (by default in: \Program Files\Quest Software (or Dell)\Diagnostic Server\Agent). It depends if the original one was upgrade or fresh install.
Optionally backup both databases (Playback and SpotlightStatisticsRepository)
3) install exactly THIS SAME version of Spotlight on the new machine. Stop the service on the new machine as well once installed.
3) take the Agent directory from the one you have backed up on old machine and replace the one on a new machine. Start the service on NEW machine only.
4) On the new machine click on Configure tab and then on Diagnostic Server icon, select Configure Playback and make sure it is pointing to the right instance and do this same with Configure Spotlight Statistics Repository. If you make any changes restart the service again on new machine.
5) if everything works fine on new machine then uninstall Spotlight on the old machine (in particular the Spotlight Diagnostic Server to make sure the old service will not start - you can disable it if you are not uninstalling).