Cannot close or disable incessent Windows 10 upgrade option

Please help me get rid of this incessant Norton download manager that keeps popping up prompting me to download and install a version compatible with Windows 10! I don't need to deal with this every five minuets! I do not intend to upgrade to Windows 10 and I have the latest version of your software for my OS!

I am plagued with FSDUI_NIS.exe and FSDUI.exe.

I am continually getting a pop-up that says "Another download manager is currently running. Please wait for it to complete and try again."

I cannot seem to rid myself of {81BF51B0-F7FB-4C71-820D-E5F434C7A7F7] constantly loading into my temp folder!