What Are System Services in the 1st place

System services are actually small helper programs that provide support for other larger programs in Windows 2000. Many of the services are set up to run automatically each time you start Windows 2000. However, if you're not using the larger programs that these services are designed to support, these services are simply wasting RAM that could be put to better use by your applications. While the word "Disable" is used here to describe the idea that you'll remove these services from memory, what you'll really be doing is changing the startup setting from Automatic to Manual. When you do, the services won't automatically start each time you launch Windows 2000 Professional. However, Windows 2000 will be able to manually start the services if they're needed. That way you won't be unnecessarily wasting RAM, but you won't be crippling your system either. Note: If you're running Windows 2000 Professional on a corporate network, you may not be able to adjust system services. Regardless of whether you can or not, you should check with your system administrator before attempting the make these changes.
Changing the startup type of a service from Automatic to Manual is a relatively simple operation. To begin, open the Control Panel, open the Administrative Tools folder, and then double click the Services tool. When you see the Services window, set the View to Detail if it isn't already. Then click the Startup Type column header to sort the services by Startup Type. When you do, all the Services that start automatically will appear at the top of the list.
As you scan through the list of services on your system whose Startup Type setting is set to Automatic, look for the services in listed in the Table below. These are some of the services are good candidates to be set to a Manual Startup Type.
Examples of services that can be safely changed to Manual :-
DHCP Client -- You're not connecting to a specific DHCP server on your local network
Distributed Link Tracking Client -- You're not connected to a Windows 2000 domain
DNS Client -- You're not connecting to a specific DNS server on your local network
FTP Publishing Service -- You don't need your system to act as an FTP server
IIS Admin Service -- You don't need your system to act as an WWW server
IPSEC Policy Agent -- You're not connected to a Windows 2000 domain
Messenger -- You're not connected to a Windows 2000 domain
Remote Registry Service -- You don't remotely access the Registry of other systems on your local network
RIP Service -- You don't need your system to act as a router
Run As Service -- You don't use any applications that run as an alias