CentOS - May 2015 - Issue getting Gnome display manager on Centos 6 to Xming on Win7

Greetings -

My objective is to get a full Gnome GUI console display to show in an Xming 
window on my Win7 box.  I do a similar thing with my Raspberry Pi so that it 
operates headless with just the power and network cord attached.  My CentOS 
6 box and the Win7 box are on the same network within my office LAN behind a 
good firewall.  For various reasons that I won't go into I am unable to 
combine them into a single box using KVM, so I would at least like to be 
able to display my CentOS Gnome GUI within an Xming window on my Win7 box. 
And I like the way that Xming works, so I would rather not switch to 
something like X2Go as I wasn't too keen on it when I last tried it.

I have done plenty of research on the web that describes how to do this, but 
I must be missing something.  I have the following things configured on the 
CentOS 6 box.

/etc/gdm/custom.conf file
[security]
  DisallowTCP=false
  AllowRemoteRoot=true
[xdmcp]
  Enable=true

/etc/ssh/sshd_config
  X11Forwarding yes
  X11DisplayOffset 10
  X11UseLocalHost yes

I start Xming on the Win7 box with the basic parameters.  Xming.exe 
:0 -resize -clipboard (one window is default)

Putty has X11 Forwarding enabled.

After logging into the CentOS box via Putty I can invoke a single program, 
such as Gedit and it will display on the Xming window, but I can not seem to 
get the entire Gnome GUI display manager.  On my Raspberry Pi, once logged 
in through Putty I just type "startlxde" at the command prompt to get
the
entire display.  But the Pi is a Debian based system running a different 
display manager, so I don't know what would be comparable for CentOS 6, and 
whether additional configuration is needed.

I have tried all the basic troubleshooting actions.  I have disabled the 
firewalls on both the CentOS 6 and Win7 boxes, and I have changed SELinux to 
permissive mode.  None of these changes made any difference, I could still 
display Gedit but not the entire Gnome GUI display manager.  So I figure 
there must be something else I need to do that I am not finding in all my 
Google searches.  Can someone clue me in please.  Thanks.

Jeff Boyce
Meridian Environmental