GWX is the process that is responsible for the tray notification. If you want to remove the threat of a forced upgrade to Win10, you need to uninstall KB3035583. Follow teh instructions I wrote here a few months ago: http://smith-wessonforum.com/138970865-post5.htmltcon, is there any sign (process, file) we could look for on our computers indicating the pending virus attack?
I looked at my task list, and I don't see anything unusual. GWX is there, but I have never heard it was a Trojan horse.
When the update uninstalls, it can take some time. Don't get impatient. Reboot when prompted, and this stage can take some time. I did one last night and it was over an hour configuring during shutdown and configuring while rebooting. One period it was a black screen for 15 minutes. But follow those instruction and that will get rid of the update. At the part after the uninstall where you are looking to hide KB3035583 so you aren't offered it again, also hide the one that actually has the name Windows 10 if that one is also in your queue list.
Questions, PM me.