How to prevent object installation?

[Alex Blekhman]

Hi,

I'm totally new to InstallShield and I need some assistance. Our
product uses some third party program (MDAC 2.7, actually) and need to
ensure that this program is installed prior to our installation. I
created InstallShield object which consists of one file
(mdac_typ.exe). I override OnBegin() handler in script as pointed in
InstallShield KB article Q105112 - "HOWTO: Detecting Which Version of
MDAC is Installed".

Now I want to examine the version of installed MDAC and in accordance
with that to launch (or prevent launching) silent setup of
'mdac_typ.exe'. So, here are my questions:

1. How can I tell to InstallShield just exit object installation if
MDAC is installed already?

2. How can I pass return code from object installation to main
standard installation? Or is there any other way to tell to parent
setup that object has been set up successfully?

3. In parent standard installation how do I know when object
installation is started? Can I ensure that object installation is
performed before installation of any of my components?

Thanks in advance
Alex