Need Help XP Is Slow?

Hi, I just Installed a new fresh copy of windows xp, on my desktop its a SYNTAX Intel Celeron CPU 1.70Ghz and 2.00 GB of Ram and 80GB Hard Drive. Now its fast but when I go on the internet its realy slow and jumps everytime I try to scroll down, The only stuff I have installed are web browsers and they are Internet Explorer 8, New verson of FireFox , and then chrome, that and the drivers for the computer is all I have installed, I dont know way its being this slow, I have tryed a 250gb hard drive and it still gose slow on the net and then I have tryed a 40gb hard drive that still did not work so then I installed xp on a 80gb hard drive so now I just left it at 80gbs what should I do, Its realy fast when I'm on the desktop and opening paint and notepad and stuff that came with xp, But its the internet I'm have truble with, I have a Cable modem dirct connact to the network card, All my other computers are realy fast its just this one so I know its not the internet connact, Please Help me, I'm out of opsoins.