PXE Failing after upgrade to SMP 7.6 HF2

After recently installing the latest hotfixes, the both of my NBS servers are failing. 

Machines boot and spin and timeout with error : Operating System Not Found. 

For some reason when I first went into the settings to check what happened, the NBS Global settings were turned off. Not the first time that I've had settings changed or set back to default after a service pack install or hotfix update. I attempted to recreate the preboot environment, and am still unsuccesfull in booting new or known machines with pxe. 

Found the following in the log for the secondary NBS:

<event date='08/03/2015 14:46:19.1530000 -04:00' severity='1' hostName='DragonberryQA' source='DSTasks' module='DeploymentSolutionAgent.dll' process='AeXNSAgent.exe' pid='5332' thread='5624' tickCount='880883719'>
  <![CDATA[ClientConfigPXEServer_Task.cpp@131: Pxe Server install path empty]]>
</event>
<event date='08/03/2015 14:46:19.1610000 -04:00' severity='1' hostName='DragonberryQA' source='DSTasks' module='DeploymentSolutionAgent.dll' process='AeXNSAgent.exe' pid='5332' thread='5624' tickCount='880883735'>
  <![CDATA[ClientConfigPXEServer_Task P]]>



<event date='08/03/2015 14:46:18.9950000 -04:00' severity='1' hostName='DragonberryQA' source='DSTasks' module='ClientPXEImage.dll' process='AeXNSAgent.exe' pid='5332' thread='5624' tickCount='880883563'>
  <![CDATA[File:ExecuteCommand.cpp,Line:4373 ERROR: The Exception have occured in ClientPXEImage task. 
Exception has occured in function tcube_clientpxeimage.cpp() at Line No 672. Type of exception is ClientPXEException. Error Description is  "PXE service is not installed. Could don't find out path of CurrentControlSetServicesSymantecNetworkBootServicePxe in registry. ". Value of Windows error code = 0 and message is " The operation completed successfully.
"
]]>

Any thoughts? Am I missing a setting somewhere? Running ITMS 7.6 HF2 on Server 2012 R2. 

NBS General settings set to on : 

• Apply NBS Settings immediately
• Enable the NBS service 
• Respond to unknown computers
• Respond to managed computers

Thanks in advance!