Windows Defender in Startup, but "stopped" in Services?

From reading this forum, it appears that I won't benefit from running Windows Defender if I have Norton 360 running.  While checking my Startup programs (in System Configuration) to conserve system resources, I found Windows Defender there (and checked).  When I went to the Services tab, however, the status of Windows Defender is "Stopped".

 

I have two questions:  (1)  Am I correct in assuming that I am wasting resources by running both Windows Defender and Norton 360?  And (2) Should I uncheck Windows Defender in the Services tab of System Configuration?

 

I am running Vista Home Premium SP2 on a 64-bit system.

 

Thanks for your help.

Don