I don't really trust anything that claims to do tune-ups, fixes stubborn errors, and optimizes performance. Products that claim such are usually shady.
I'd stick with a pure antivirus/antimalware program that doesn't claim to do everything. Usually optimizations, registry cleaners, tune up your system etc. are all bogus.
The best tune up is for you to go in and uninstall all the Windows components you don't need and to manually stop and deactivate the services you will never use. Then you can deal with caching and hardrive behaviors.
Seeing as how this is free though, go ahead and try it. I've gotten some decent software on these giveaway of the day things (alot is bogus though). Check this site for those
http://www.giveawayoftheday.com/