If you go to the Cointrol Panel and select to view by the 'Small Icons' option (upper right corner), you can gain easy access back to all the control panel functions.
Adminisitrative Tools->Services will provide more information about what the service is and what impact it might have on other services.
Like Ripley stated, you should not be able to hurt anything disabling "Startup" programs, but you can do damage in the "Services" list.