Another item in the Windows clean-up (somewhere under "advanced") is to remove all but the latest registry back-ups. This was really clogging up the hard disk in my laptop, and has given it a whole new lease on life.
Regular cleaning of the registry helps, as does regular scanning for malware, and using something like Startup Inspector For Windows to shut out the startup crapware that many software vendors insist on installing.
Making the CPU run faster might help, but if the bottleneck is elsewhere it won't. I use a magical system monitor called "Rubber Ducky" which is freeware from an outfit called "Mimarsinan". In the space of a stamp it shows memory usage, CPU activity, net traffic, hard disc access, and probably plenty of other stuff, all with a rubber ducky swimming in an aquarium. It caused me to increase my memory and cured one source of slowness.