OK - we're getting somewhere!
Windows XP (assuming you have XP Pro, as XP Home doesn't have a web server) doesn't have the CDONTS component. CDONTS is an old, outdated component that was only even included in Windows 2000 for backward compatibility.
CDOSYS is the component you need to use in Windows XP. You need to change your code to conform to this component which is not overly hard to do.
If you search google for CDOSYS ASP you'll find heaps of articles on how to do this.
That said, you *can* install CDONTS on XP if you wish however you're really taking a step backward.
Cheers,
Andrew