My computer takes a few extra seconds to load anything, and anything that installs something will give me massive lag even if it's not intensive. To add on, now, when I download a game from Steam, my entire computer has system-wide lag of my mouse and the entire computer and I can't even voice chat without earbleeding audio that freezes and repeats so much that it actually scares me. My computer has nothing taking up 99% of RAM or Disk, CPU, or Network. Now, my computer is super slow when doing basic tasks such as YouTube - which it never has had any problem running over 100 tabs and playing like 10 of them! YouTube stutters and freezes and repeats audio or frames, and it's really scary (sometimes earbleedingly loud) and annoying. They also uninstalled all of them after they finished, but left on extensions such as Web of Trust, Disconnect and Ad Blocker. They never went inside the computer or anything, but they installed and ran AVG, and after that they ran Avast!, after Avast! they ran Malwarebytes, and then they ran CCleaner. I had accidentally installed something with a virus, so I brought my computer to a repair shop.

Avast vs avg windows 10 2016