Type in msconfig and hit enter, then click on the startup tab and remove the ticks from the offending items (there is probably loads more you can remove too, either google or ask here)
Once your done you'll need to restart, you will get a warning after the restart, just click in the don't show this again box and click ok.
In addition, within msconfig there is also a services tab. As per Chucks advice, search on net for each ticked item and untick any that are not needed.
A very useful (and very small) program for XP is StartupMonitor http://download.cnet....00-2094_4-139845.html which, every time a program tries to add itself to the startup, lets you decide whether to allow or not. It just sits in the background and a small pop-up window appears whenever something tries to sneak its way in.