>In Windows NT Explorer, under Tools, Folder Options, I can find the entry which tells IE to open whenever we click on a HTML file. I would like to change that but it is not listed. Where is this association coming from?

---

You can also do this in the explorer window
Choose Options/Folder options
the choose the TAB file types and there you can change what you want.
The names of the menus and the TAB's can differ, cause i have a dutch version of windows (Me) and i simply translated them.