"J. P. Gilliver (John)" wrote

| Turnpike software worked at first on Win64 then the problem
| probably has nothing to do with 32/64.
|
| Those who know a lot more than I say that up until, but not including,
| the final release of 7-64, the 64-bit OS included a 32-bit shell (I
| think shell was the word), which was "switched in" (?) when software
| needed it.

There are 2 things. One is a "stub" that allows 32-bit
to run on Win64. They're not actually very different. So
32-bit can run on all Win64, including Win10.

The other thing, that people might have been talking
about, was that, if I remember correctly, Explorer/IE/32 was
the default at first because they hadn't finished the 64-bit
version. Then for some time (maybe still?) you could choose
to use the 32-bit version. Eventually I think it was removed.
So thast could explain how a shell extension worked and
then didn't.