Blank Threat detected boxes

I’m getting Threat detected boxes that are blank. There is nothing in the list of threats, and when I try to exit it, It tells me there are unresolved threats. Why is this happening…? I recently got a trojan from something I downloaded, but norton got rid of it. The Blank boxes started appearing then, so I used the norton power eraser, and it detected a few things that I knew where legitimate. I let norton erase them anyway, but the blank boxes still appear.