In all my years of computer support, no one has ever come to me and asked for my assistance to slow down their computer systems.  Maximize the speed of my system is always the request.  Nobody wants to spend most of their time at the computer waiting for programs and pages to load.
There are only two ways to increase your computer system speed:

• Hardware Enhancements
• Software tuning

Hardware Enhancements would include doing things like adding more ram, installing a newer and faster hard drive, cleaning the interior cpu and power supply fans and case.  Hardware enhancements are best done by a qualified computer repair technician.  Opening the computer case will void the remainder of your warranty if applicable.  The ram has to be matched to your motherboard correctly before being installed and accidentally disconnecting or breaking something during cleaning could temporarily or permanently disable your computer.  Leave the Hardware to the certified techs.

Software tuning would include doing things like cleaning unnecessary files like Recycle Bin, Recent Documents, Temporary files, Log files, Clipboard, DNS Cache, Error Reporting, Memory Dumps, Jump Lists, Temporary files, history, cookies, super cookies, Recent Documents, Temporary files, Log files, Clipboard, Error Reporting, Memory Dumps, Jump Lists .  These are all the files that windows accumulates during everyday use.  Some are for windows to use as quick reference in case you revisit a recent web page.  If not cleaned occasionally, they can become quite large and cumbersome.  They become so large, they are no longer able to be quickly referenced.  I could describe how to clean these files one by one but that is not necessary. There is a great free utility available from Piriform  called CCleaner.  It does all of the cleaning for you. 

Download and install CCleaner from the Piriform website.  When it installs, you should see the interface.  Click on 'run cleaner' in the lower right corner.
Agree to have your files cleaned.
Notice all of the recovered space once cleaning is completed.