Press CTRL-ALT-DEL while in Windows and bring up the Task Manager. Notice how many programs are running in the background. Each program steals memory and CPU cycles. Offenders include: Adobe Gamma Loader, Fast Find, msmsgs (Messenger), Office Startup, qttask (Quicktime), System Agent, Real Player, Norton. To stop programs from automatically starting, remove the file from the Programs - Startup folder, left click on the icons in the System tray and turn off automatic loading, or consult the help file of each program to turn it off. Run MSCONFIG to get a list of programs that run on startup and remove unnecessary ones.
Disable Alerter, File and Print, FTP Publishing, Indexing Service, World Wide Web Publisher, Messenger, Computer Browser, Routing and Remote Access, Smart Card, Smart Card Helper, Terminal services, Uninterruptible Power Supply if they are not being used. You can always turn them off and test your machine, before setting them to be disabled on startup. Run "services.msc" from the Run.. menu and Disable any services that are unncessary.