When you press CTRL-ALT-DELETE and select the processes tab,you will noticed that there are a lot of processes running in the background of your computer. Its very hard to tell which ones are safe to close just by looking at the list, and often times ending the wrong process will crash your system and you will lose any unsaved data.
In my personal computer at home, after the system boots up there are over 60 processes running in my task manager, many which have accumulated from various program installs over the course of two years. While none of these processes are necessarily causing my computer any harm, they are definitely eating up CPU resources while idling in the background. If you are interested in learning what exactly are all the processes running in the background, check ProcessLibrary.com which is a great site for searching up unknown processes.
The solution I use to getting rid of all these unwanted processes is a program called KillProcess which can terminate any process on a Windows machine in a matter of seconds. The program is able to use a "Kill List" in order to determine which processes are needed by windows and those which are unnecessary.
The program will execute the kill list in a matter of seconds and terminate all those bloat processes. I personally use a modified version "Clean XP.lst" kill list from Orange Lamp in which I have added a few processes I would like to keep to the list. All in all after using the KillProcess program I have about 19 processes running in the background, a huge difference from the 62 I have at boot up.