Windows Defender can be started in windows XP from Start > All Programs > Windows Defender menu. It is an optional download for windows XP. In case you do not have this program you can download it from Microsoft's website. It has become an essential software for windows. It includes a powerful antispyware, a intrusion detection and prevention utility, and a tool to find out the currently running software on your computer, you can also find out the software that start with windows. You can find all this information in detail, you can also know the processes that are running, and unlike in the task manager you can see the path of the process. And you can easily determine if it is harmful or a fake and disable/ terminate it from inside the windows defender.
To find out the currently running programs, first open windows defender, and then Click on the Tools icon in the menubar. A Tools and settings windows will be displayed . Under Tools Click on software Explorer. Software Explorer window will open. You will see a drop down box with Category "Startup Program" Selected. You can use the scroll bar to see all the entries there and if you want to know more about a program, click on its name, and you will see detailed information on the right side of the window. If you find an unwanted program you can disable it or remove it from the startup using the buttons at the bottom right of the screen.
Click on the drop down menu and select "Currently running programs" . The first section is "Microsoft Corporation", you can skip them. As you scroll down, you will see other programs with their Publisher's name mentioned. You should be careful of entries with "Unknown publisher", you can select a programs name to find its details. If you identify a suspicious program/ process, you can end that process from the button at the bottom right of the screen, or open task manager from another button.