I may be mistaken, but XP never loaded anything not necessary for it to run when I start the computer. Go to All Programs -> Startup and you'll see what apps runs when you start up. On all my computers, the entry is (empty).

The things (processes) XP runs when it starts up are things it needs to do its various tasks. If there are applications in your startup folder, they're usually put there by the guys who sold you the computer (a.k.a. "bloatware"), or by you, because you want something to be instantly available. XP by itself does not put any apps there.