Windows Installer issue?

Hi,

I having some problems with at least 2 main applications:

1. AOL Active Shield antivirus
2. ATI Catalyst 7.5 drivers

I guess that both issues are related. When I try to run the AOL AV it goes
almost until 100% but the installer roll back and dont allows me to install.
I already have sucessfully installed that antivirus on other Vista OS.

When trying to install to the Catalyst driver I have other behaviour, the
installer goes until the end, says the installation is completed, ask to
reboot. Ok, but no folders appears, just one called "Catalyst Manager
Installation..." with option to install or remove the driver application.

I have forced the package to cause a proposital error after a lot of tests,
so I have discovered that my Vista is actually unable to install. As a simple
answer, if I try to remove the Catalyst, after all the installation process,
the remove tool says: no software yet installed (such message).

Well, my doubt resides if there is some way to reinstall the Vista Windows
Installer or someway to fix it. Of course, if this is really a Windows
Installer issue.

small detail: looking at that memory monitor and have noticed while
installing the Catalyst driver a lot of errors (more than 1,200 and counting).

Thank you for all support!