Vista blocks Netscape 9.3b

When I attempt to open Netscape 9 recently with Vista operating system I get
this error message.

"The program must close to allow a previous installation attempt to
complete. Please restart."

I am at sea where this message is coming from? Whether Vista, McAfee, or is
it a Netscape error message? I suspect that it is Vista.

I had been using Netscape 9.3 routinely and all at once this pops up. After
this error message appeared, I reinstalled Netscape 9.3 three times to no
avail. The message appears every time that I start Netscape normally from a
desktop icon or the Start Menu.

What I can do is start Netscape from the Program screen by right clicking
and select open as Administrator. I get a warning from the Vista User
Account nonsense but I can open and use Netscape, in fact, am using it now.
There is only one User Account on my computer.

I just cannot open Netscape 'normally'.

How do I get rid of this 'error' message as I want to use Netscape and
I don't want to go through the steps of 'running under administrator' every
time. Also, I cannot use Netscape as my default browser under these
circumstances since it will not open if I click on a hyperlink on my screen
in another program like my mail or Word applications.

Thanks