Thats were you can make use of BlackVipers little offering as his explanations of each service and the recomendations he makes on them will by trial and error force an improvement in performance, however it is not without it's risks as some programs you may require may use some of the obscure services listed there. Short hint on how far you can go with it is that I have managed to get a fully working computer with net connection running with as little as eight services, did not go into how secure or stable it was at the time but it can be done.