Can anyone point me to an article which explains how Windows Search works.

I've used TWEAKUI to run the Classic Search.

Sometimes however the results seem to include far more than the "obvious" solutions which match the wild card search.

I had an example to use, but I've just re-run it after checking TWEAK UI, and it seems to have changed.

However, I searched for scanreg*.exe, and got approx 30 results, including .reg files &.ini files.