I ran NPE, because of a virus called Stij.exe, and it deleted Technic Launcher...Why?

So, Technic Launcher is a branch off of minecraft, the popular sandbox game where you build. Basically it lets you run Minecraft with mods without "installing" the mods. Norton Power Eraser (NPE) basically looks through EVERY SINGLE ONE of your files until it suspects a problem, and once doing so, it deletes it. Any ideas why it does that?