There are many sites out there that will help you with this, but this one is a good start..
Stick with his 'safe' config. for a start and you should be fine..

http://www.blackviper.com/WinXP/servicecfg.htm

"SAFE" Configuration ~ This is the configuration that 95% of the people will be able to use with little or no side effects. It will also minimizes the amount of "errors" that is reported in the Event Viewer. This does not guarantee it will work for you, but if adjusting your services scares you, this configuration would be a good starting point.