Norton inactive or disabled

We have a problem with Norton Internet Security.

It basically stops working.

The icon in the toolbar disappears and the desktop icon (shortcut) becomes dead and will not open up the Norton GUI.

A look at the running processes shows that 2 Norton processes are still running, but there is no sign of it in the toolbar.

We have followed the advice on the Norton website for this problem i.e. to run the Norton removal program, reboot, and then download the latest version of the program and re-install.

Within days the problem returns and we are unable to access Norton again.

The PC in question is a Toshiba Satellite P850-31L with a Intel Core i7-3630QM and 8GB ram, running Windows 10.

However, we had this issue on the same PC when it was running Windows 8.1.

We had to run the removal tool and reload Norton several times on that operating system as well.

When we upgraded to Windows 10, we replaced the hard drive and did a clean install of Windows 10 64-bit.

So there is no possibility of something being passed from the "old" system to the "new" one.

Each time we run the Norton removal tool it has run completely and reported that it has succeeded. 

Each time we download Norton Internet security, we are downloading the latest version from the Norton website.

Each time we install Norton it activates correctly with the users key and the correct number of days left is shown.

But every time go through this process the problem returns within days.

I am helping the owner of the PC with this problem and I deal with many PCs running N.I.S. in the field.

Some of them have had this issue before, but none have had it over and over again.

As a work-around and to cover the PC in the short term (also to rule out foul-play)   we have installed AVG.