Replying to computer ppl help

In msconfig what program thingies need to be on at the boot of the computer? HP seems to start every single program at boot and its taking up so much resources. I know some of the shit I can disable but some of the stuff is weird (like tcms.sdl or something) and I dont know if its critical or not. I know thers like 1 or 2 programs that you have to have on but I dont know which. By the way I have Windows XP if that makes it any different.