I'm assuming you are using Internet Explorer in XP.
In IE, click Tools, Internet Options. You should get a pop-up box. click the general tab (probably already showing). Click settings (in the Temp. internet settings group).
You should now get another pop up titled settings. In the top menu make sure the top radio button is selected so that your browser checks for a new version of a page each time you visit.
If you do not select this option then Windows may load an older version of the page stored in your hard disk cache.