Google how to turn off services and a list of services you don't need and can turn off safely. It saves some RAM, reduces load on your CPU, and increases startup time. You can also type "msconfig" in your search and run that. Go to the Startup tab and unclick whatever is you don't need.
DON'T TURN OFF SERVICES FROM THE SERVICE TAB IN MSCONFIG. Some services are dependant on another, and act as a chain process to accomplish something. Some services must be kept on for your system to run properly, please Google what each one does and make sure your system doesn't need it before turning them off.