DevStudio 9 - Detect XP vs. Vista in custom VBS action how?

[chris.shea...@gmail.com]

For a variety of unpleasant reasons, I'm stuck with DevStudio 9 and am
not allowed to upgrade.

Management wants to install to "all users" under Vista, but "current
user only" under all other OSs, and this needs to happen without any
prompting of the user. I've got a custom VBS action defined that says
SESSION.PROPERTY("ALLUSERS")="2"
but that sets it to install to all users in all OSs, not just Vista.

Does DevStudio 9 have the ability to check, inside a custom VBS
action, which OS it's running under?

Thanks,
Chris