Windows XP has a lot of services, some of which are not needed for normal use. To speed up Windows XP you can disable these services.
Go to Start > Run, type in ’services.msc’.
To turn off a service, double-click on it and select Disabled under Startup type.
Disable the following services:
Alerter
Background Intelligent Transfer Service
ClipBook
Computer Browser
Error Reporting Service
Help and Support
Indexing Service
IPSEC Services
Messenger
NetMeeting Remote Desktop Sharing
Network DDE
Network DDE DSDM
Performance Logs and Alerts
Portable Media Serial Number
QOS RSVP
Remote Desktop Help Session Manager
Remote Registry
Secondary Logon
Server
Smart Card
Smart Card Helper
SSDP Discovery Service
System restore Service
TCP/IP NetBIOS Helper
Uninterruptible Power Supply
Universal Plug and Play Device Host
WebClient
Windows time
Wireless Zero Configuration
WMI Performance Adapter"