Thoughts based on some quick research.
When the gretl installer is being run on Windows there are three
main cases to consider:
1. gretl is being installed by someone who has admin (or at least
"power user") rights, and this person will also be using gretl.
I believe that's the most likely case, at least in the American
academic sphere, and in this case what we do currently is fine.
2. gretl is being installed by an admin user, on behalf of someone
else who doesn't have admin rights but who will actually use the
progam. In this case the install should go OK, though as Sven
points out it will redundantly create a gretl userdir tree for
the admin user. When the ordinary user runs the program there may
be some permissions issues on saving settings. This should be
fixable without too much difficulty.
3. An unprivileged user is trying to install gretl on their own
account. This will fail at present. It's possible we could set
things up so that it'll work: don't install gretl into
PROGRAMFILES but into a per-user directory; don't attempt to write
registry keys under "Local Machine", only "Current User".
MSDN says:
"During setup your application should check to see whether the
application is being installed by a user account having the
privileges to write to HKEY_LOCAL_MACHINE. If your setup is not
run by a user with write permissions to HKEY_LOCAL_MACHINE, the
application should notify the user with a message such as, "You
are not allowed to install this application for all users on this
machine; do you want to install this application for personal
use?" All users should be able to install an application for their
own use."
Conversely, if the user does have admin status we could ask: "You
are installing gretl as an administrator; will you be using the
program yourself?" -- and create a userdir tree only if the answer
to that is Yes.
I'm not sure yet how much of this can be done with the current
version of Inno Setup, but I'm trying to figure that out.
Allin.