I dont understand what the Norton removal tool is????

My computer came preinstalled with Norton 08 but I didnt want it on there so I went to add/remove programs and I got it off there. Norton  said Norton internet security 2008 has been succesfully uinstalled! I then went to install Norton internet security 2009. My question is- do computers that come preinstalled with Norton have the norton removal tool built in, and have I successfully uinstalled norton 08? Im just really confused here???