98 and XP can use msconfig
if you are using windows 2000, you can either copy the msconfig file from winXP machine, or you can download some software like winOptimizer, regCleaner(recommend). or you can modify your registry.
HKEY-LOCAL-MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
HKEY-LOCAL-MACHINE\Software\Microsoft\Windows\CurrentVersion\Run