Title:Unable to Install SEP RU5 on Windows 7(Windows Installer could not be accessed error 1719)

Steps Tried:
Downloaded and Installed Windows Installer Cleanup
Unregister and reregistered the msiexec
Installed Lusetup first,able to install liveupdate successfully
When clicking on Symantec Antivirus.msi getting this error message
Checked for Windows Installer it was started and Manual,changed it to automatic and tried,it doen't works.

Tried fo follow this doc:
http://support.microsoft.com/kb/555175
http://support.microsoft.com/?id=319624
http://support.microsoft.com/kb/315346
however nothing has the instructions for Windows 7

Searched from this forum and found this,however all these instructions are only for Xp/2003
https://www-secure.symantec.com/connect/articles/error-windows-installer-service-could-not-be-accessed-when-installing-symantec-endpoint-pr-0

Since it's Windows 7,i am not familiar with it , dont know how to provide the Dcom permisions any suggestions or Solution for this

Please help!