I clear out all the Prefetch files. (In your Windows folder, open the prefetch folder and delete all the .pf files)
I use Glary Utilities to clean my registry (www.glarysoft.com) - You need to watch to download site to not download the incorrect program. Also, look at the check offs before installing - it tries to offer you the Ask search engine. Very good program.
I use malware bytes anti malware.
I use Spy Bot Search and Destroy.
Then I will defrag.

All these are free programs that I use to keep my computer running fast.