[jcarerra]

OK, now there is new information...that it is conceivable that Windows did it. But how did it know which extensions to change?

And I assure you, unless I made a terrible mistake, I did not answer any question that clearly related to file associations--and don't remember ANY unexpected questions coming up.

But it happened, so SOMEtHING made it happen.
It appears as if the "Set your default program" was executed with Calibre selected--but I did not go into Control Panel during install. Puzzling mystery.

Also, I don't understand how/why Calibre makes NO associations. If you install it, should it not open epub files, for example?

Although it is not clear how this happened in my case, would it be warranted to EXPLICITLY have a dialog during install for user to select what extensions to associate?

And oh, I was in DESKTOP mode. Always am.
Only bring up the tile screen if it is an accident

I apologize a little bit for my tone. I was highly annoyed at having to manually change all those associations (and many are still associated since i don't know what the 'normal' association would be). As I mentioned before, the only thing I remember being a change from a straight install was deselecting the "put in path" item. I allow for a 5% chance of there being something else, but if it had the word 'association' in it, I would remember that.

A question--if you uninstall a program, does the uninstall process return associations to what they were before? If so, I could uninstall and reinstall and WATCH closely for what questions come up.