When launching the installer to upgrade from a Python 3.5.0 install to 3.5.1, the path shown on the Install button is incorrect. Clicking the button installs to the correct location.

This is a regression from 3.5.0 that will cause a lot of confusion. It ought to be fixed.

Fix attached:
* moves the UI update to the correct time (*after* we've detected the path)
* fixes a launcher detection issue I noticed
* removes a duplicated function

Launcher detection still isn't quite right - another patch coming.

Man, dealing with the launcher is hard. But I've got it about as good as I can:

* when installing 3.5.1 over 3.5.0, user has the option to update/not update the launcher (no option to uninstall at that time)
* after installing 3.5.1, launcher can be added via Modify, but not removed - the checkbox is now disabled with this change
* with 3.5.1, the launcher has its own entry in Programs and Features (from a different bug)
* uninstalling 3.5.1 does not automatically uninstall the launcher

This patch updates the help text in the installer to better explain what's going on, and now gets the "requires admin" icon correct.

Larry - this change is fully contained to the installer and (along with the original part of the issue above) should avoid a lot of confusion once we release. Can I have it in 3.5.1? I'm happy to rebase and push directly to your repo.

You can have it in 3.5.1, and we can negotiate about how to get it in.

New changeset 8537ec50c254 by Steve Dower in branch '3.5':
Issue #25715: Python 3.5.1 installer shows wrong upgrade path and incorrect logic for launcher detection.
https://hg.python.org/cpython/rev/8537ec50c254

As you can see, I've now pushed to the main 3.5 branch, so feel free to cherry-pick from there or give me the word and I'll graft it into the releasing repo for you.

I also forward merged all the 3.5.1 NEWS into default. Not sure how that normally happens, but it was easier to do it with a big copy-past than try and figure out the merge conflicts...

Fixed in 3.5.1 final.