Problems installing Symantec Antivirus Corporate Edition

I was having problems installing Symantec Antivirus Corporate Edition client version yesterday in my work place.
There are 2 methods to install Symantec Antivirus Corporate Edition.
First method is put in the CD and wait for the autorun to appear and click on the “Install Symantec Antivirus” bar.
Symantec Antivirus Corporate Edition CD autorun
Second method would be browsing the content of the CD, and run Setup.exe from the SAV folder.
Browse Symantec Antivirus Corporate Edition CD
Either method is the same. First method actually has an interface where you can click the button and it would call up Setup.exe from the SAV folder. If your autorun has been disabled, you can use the second method which is browse the CD contents and run Setup.exe manually from SAV folder.
The server version of Symantec Antivirus Corporate Edition has already been installed. I wanted to install the client version of Symantec Antivirus that will be managed by the server yesterday and was unable to do so.

-->
Usually during setup, it will show you a few options that is client server options, setup type and network setup type.
Client Server Options
Symantec Antivirus Corporate Edition Client Server Options
1. Client Install - Choose this option if this computer is to be unmanaged or managed by a computer running Symantec Antivirus Server Edition.
2. Server Install - Choose this option if this computer is to be a Symantec Antivirus Server and will be managing other client computers.
Setup Type
1. Complete - All programs and features will be installed. (Required the most disk space.)
2. Custom - Choose which program features you want installed and where they will be installed. Recommended for advanced users.
Network Setup Type
Symantec Antivirus Corporate Edition Network Setup Type
1. Managed - Choose this option if this computer is to be managed by a computer running Symantec AntiVirus Server Edition.
2. Unmanaged - Choose this option if this computer will not be managed by a computer running Symantec AntiVirus Server Edition. For example, your home computer.
Problem I encountered while installing the client install was, the options above was not displayed but I could still go on with the setup. However, after the installation just started, I got an error message saying “This MSI must be launched through setup. For more information, please visit http://www.symantec.com/install
This MSI must be launched through setup. For more information, please visit http://www.symantec.com/install
I browsed the CD and ran the Setup.exe manually. Still the same error message and couldn’t complete installing the client install of Symantec Antivirus Corporate Edition. I ran Symantec AntiVirus.msi, still the same error message and couldn’t complete installing.
After trying to install a few times and failed, I noticed something different when the setup was being run. For a very quick few seconds, the setup displayed a very important information saying “Searching for related applications. Found application: {C6F5B6CF-609C-428E-876F-CA83176C021B}
Searching for related applications. Found application: {C6F5B6CF-609C-428E-876F-CA83176C021B}
I believe that {C6F5B6CF-609C-428E-876F-CA83176C021B} entry is located in Registry and it is to identify a software.
I noticed that this computer I was trying to install the client version of Symantec Antivirus Corporate Edition already has Norton Antivirus 2005 installed! After uninstalled Symantec Antivirus 2005, rebooted the computer and now I am able to install the client version of Symantec Antivirus Corporate Edition.
I no longer have the screen which says Searching for related applications. Found application: {C6F5B6CF-609C-428E-876F-CA83176C021B} and also I now have the client server options, setup type and network setup type during installation.
Not a very big problem but I guess I was lucky because I was able to locate the problem at my first try.