Services.msc

To stop programs and unused services.

Click Start > Run and in the Run Box type services.msc (lower case text) Hit Enter / Return this will open the services window  and shows every service running on your PC click / highlight on any one and XP will tell you about it in a window (top left) and if you double click it a window will open that will give you the option (to stop it running, start it running, to put it on hold “manual” and if it is needed by XP it will start the service, if your not sure use the manual setting then if it is not needed by XP it wont start it, if you think you have services running that you don't need its a good idea to find out exactly what they are and do within your system as each user requirements may be different.