T-N-Z

Hi there, I have been running ESET Smart Security for a couple of weeks now, yesterday, I started having some problems after creating another temporary user (without admin rights) for my friend. We logged in into that account, used it a little, and all of sudden Windows Defender started up, and it starts doing quick scan. I believed everything was fine so I ignored it. But today, I log back into my main account, like usual, and now I have 2 antiviruses running alongside each other for some reason. Before this, I think Windows Defender disabled itself when Smart Security was installed, also Windows Defender is doing something, so SSD's disk usage is 100%, and my laptop gets frozen after 5 minutes. I also get Windows Notifications that I should enable Windows Firewall and should do a Quick Scan. I think making another account enabled Windows Defender on my main account too. Smart Security is enabled, but how do I disable Windows Defender? I am on Windows 10.