Ok... This issues seems to be resolved.
I didn't get any replys to my original post yesterday, but I managed to resolve the issue myself.
Hopefully this follow-up might help someone in the future.
So here's a brief recap of the problem...
Yesterday I had to abort the installation of the MS Web Platform Installer. After I aborted the install process (via using the Task Manager) to kill the process, what ever version of the Installer got installed (and how ever far the install got), the Web Platform Installer 2.0 Beta would be stopped by the OS before it would load. The details are in the original post, but maninly it looked like the problem was a corrupt or missing MSVCR80.dll file.
This error would happen even when I tired running the WebPlatformInstaller.exe directly from the MS Download website: http://www.microsoft.com/web/downloads/platform.aspx (I then selected the 2.0 Beta Version)
Solution which seemed to work today:
This morning I used the normal widow's software removal tool in the Control Panel to uninstall the MS Web Platform Installer, and anything else I could find which it installed yesterday... All of them turned out to be various SQL Server components. I'd say there were 7 or 8 components. About 3 of the SQL Server components would yield a message when I tried to uninstall them to the affect that those components could not be removed because they had no associated program... but that didn't seem to be a problem.
I double checked the registry to make sure any reference to the Web Platform Installer then seemed to have been removed... Things looked ok with that.
Finally, I deleted the version of MSVCR80.dll file (version 8.0.50727.762) which I had found on the Internet yesterday... and which seemed to be the wrong version. That leaves me with NO version of that file in the System32 directory... but that does not seem to be a problem.
The last thing I did was to reboot my machine, then went to the http://www.microsoft.com/web/downloads/platform.aspx and again downloaded the execuitable installer file...
This time, the installer installed itself ok, and seems to run ok.
I have no real "root cause inalysis" to share here... just the steps I took which seemed to resolve the issue.
Cheers!
RJ