How can I mask my IP address when people access my website

Hi all and anyone who can answer.

So I’m hosting my own website in a Windows 2003 Server and I can access it with my domain name that I bought with no problem, but in my website when I click on the links to go to a different page of my website, the IP address shows up http://99.99.99.99/aboutme.htm, and so on for my other pages. I called my domain name supplier and they told me that it wasn’t a setting they had control of, it was something I would have to set in my server. I want it to show my different pages like this http://www.domainname.com/aboutme.htm, and etc…

Please let me know some guidance or help on how I can go about this. Thank you very much

rxnzero