Stupid question, and probably very easy answer. Basically, in XP, if I create a Notepad file on the Desktop, and name it something like 'index.html', the file shows up on the desktop as 'index ...

To add a page to your desktop, go to Control panel, Display, Desktop, and choose "Customize Desktop". On the "Web" tab click "New" and add the location of your to-do list HTML file, as shown.