SCCM 2012 - Removing an old Site System

I recently had to remove an old site system (DP) that had been decommissioned.

If you ever get faced with being unable to delete the site system a useful method for removal is listed here:

http://myitforum.com/myitforumwp/2013/01/17/sccm-2012-removing-a-site-system-from-the-console-that-is-no-longer-online/

Worked well for me, especially as I didn't want to wait for the Site Component to pick up the roles I removed as eventually Component Server will get removed.

The error message you receive when deleting is:

-----------------------------------------------------------------------

The server “\\<server_fqdn>” cannot be deleted because it contains the following site system roles:

Component server
-----------------------------------------------------------------------

The registry key to use is:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SMS\Components\SMS_SITE_COMPONENT_MANAGER\Component Servers\[SERVERNAME]