Do not set program assocation when opening a file

When I open a file with an unrecognized extension:

- The first time it asks me to select a program, and also offers a checkbox to set the program association
- If I uncheck the checkbox the first time, then the second time it asks me to select a program, but there is no checkbox to set the program association - it's automatically set for me

So I have 2 questions

1. Can this behavior be overridden so that I get the checkbox every time I open the file?
2. How can I wipe/delete/clear out the unwanted association that Windows set for me the second time?

For question 1:

Try this reg file I made you, I think I understood your question correctly. Download
Modified = Install
Original = Uninstall

For question 2, there are a couple ways.

Noob Way:
Press WinKey + S
Type "default programs"
Use that gui to change things.

Pro Way:
Head into your registry under "HKCU" and/or "HKU\SID_Classes" and change things there.