There is something called an Active Desktop, at least that is what it was called in the past. It allows use of a HTML file for the desktop and then you have a very flexible way to customize the desktop. It has been a long time since I tried it so I might have the details wrong. You can ask in another forum or a newsgroup about this.
In XP, when I click on the desktop and select Properties I get a Display Properties box. When I go to the Desktop tab and click on the Customize Desktop button, then click on the Web tab (got that so far ) I get a box for entering web pages to be displayed on the desktop. That is probably worth exploring. If you have questions, ask elsewhere; the topic is out of scope for here and I don't remember much about it, even if it is what I remember using.