System Infected: Trojan Backdoor Activity 670

starting 9/23/2022 afternoon starting getting orig Norton msg "Outbound Traffic Detected..We have detected a large amount of suspicious outbound traffic on your system.  You computer may be infected with something that Norton Power Eraser can detect and remove. Do you want to run Norton Power Eraser?"  I said NO until I could figure it out.  At same time I figured out Spotify had been installed to my computer without me knowing about it until it started popping up wanting me to start it.  Uninstalled that.  Then started getting ongoing notification msgs ev couple of minutes: "Norton blocked an attack by System Infected Trojan.Backdoor Activity 670".  Used Norton to scan several times but it never found anything.  Even restored PC back to 5 days ago, re-updated Norton & other apps. Rebooted - Spotify had been reinstalled-uninstalled again. Got all the same messages as before about outgoing traffic and said no again to Power Eraser, then the repetitive notifications began again.  Looked again at the details which gave me trail "Attack was resulted from \Device\HarddiskVolumn4\Users\D-LAS\Appdata\Roaming\oz4sjmiy\WHOST.EXE.  So I found the file but still didn't know what it was.  Internet research led me to NetSupport Ltd - NetSupport Client Application is an application platform for remote access across pc networks.  It did not show up in my Apps & Features, but was in my Startup Apps.  Turned that off. Then when to Task Manager & found it in Processes tab- right-clicked "End Task".  Then went to Startup tab and had to "disable" it there.    That has now stopped all of my non-stop popup notifications.  Once my backup for my personal files has finished.  I will run Norton again and maybe use the Power Eraser even to see if it will delete the program.  Since NetSupport Client Application doesn't show up in my Apps I'm trying to figure out how to completely uninstall it it Power Eraser doesn't.  More research...but at least the non-stop pop-up notifications have stopped.

You might try scanning your system with Malwarebytes free scanner.  You can download it at this Link