In the first tab that is open called "Visual Effects", you can edit how good your computer runs or looks. The will be a box that says "Performance" click on the button there that says "Settings". Once this is open click on the the "Advanced" Tab. Click on the "View System Information" link in the upper left hand side of the screen. Now what you want to do is open "My Computer". It will prompt you if you would like to restart. After done selecting everything click accept and done. They just wont waste your valuable ram if your not using them. These programs will still work if you launch them from a shortcut or link if you click on them. In this tab, disable anything that isn't important such as google desktop, java, adobe, printer software, dial-up or other nonsense. What you want to do is extend the column at the top that says command. The names of the items in here are not in any way as strait forward as the services tab.
Once you are done in here, open up the startup tab. But, a good example of what to turn off would be the wireless service if you are connected to the internet through a ethernet cable. Remember that it is extremely important dont turn off anything important or that you dont know what it is. In the services tab you can search through the programs listed and disable them from starting up. First start by clicking on the services tab, dont worry about anything else for now.
It may seem confusing at first, but its rather simple. In the start menu, click the button that says "Run" (If your using Vista, search it in the search bar) After that window opens up, type in the text box "MSConfig." This will open up the system cofiguration program. Another thing that you can use to speed up your system that most people don't know about is configuring the startup of your computers task bar programs.