http://www.google.com/search?sourcei...o+use+msconfig
That link provides lots of information about the Microsoft Configuration Utility. The link I gave you is one of the easiest to understand. Be sure you are looking at information for your Operating System.
Whe you uncheck items that do not need to boot everytime and can be started via Start > Programs when you need them, you must then click on APPLY and OK. The next time you reboot, Windows will popup the Utility asking if you want to make the change, tell it yes, and check the box to not remind you anymore.
Thanks