Norton App

I have had Norton for about six months but I have "lost" the App- No matter how many times I download and install the software, I get the same result.  The App is there and when I am asked to restart the system poof (A technical term) the App disappears

Are you referring to the Norton 360 app or another Norton app?  

What device and operating system version are you using? 

Did you have another security software on your device before installing Norton? If so, did you fully remove it using the removal utility for that software before installing Norton?