for Process Explorer (free). Download and install it. It will list everything running and show you what it does. You can stop or remove what you don't like.
I'm running Windows XP Media on a one month old Sony Vaio VGN-N110G and was wondering what kind or even if there were some programs running in the background taking up ram while the laptop is on. I know about msconfig and I know how to stop things from starting up automatically when I boot up, but I still feel like 512mb ram should be a little faster after coming from 256mb on my last computer. If there are programs running, how can I stop them?