Can you see it? It's a black square with the "X - close" option on the upper-right corner... it always appears on the same place in lots of websites.
Here are some facts that may help you out help me out.
1- It happens in both Google Chrome and Internet Explorer.
2- If I turn my Adblock off, the advertisement appears inside the borderline(square).
3- I have 4 extensions on chrome, but I've tried deactivating and nothing changes.(since it happens in IE also, this may not be the problem).
4- I've tried using Avast scan, Malwarebyte scan and Adwcleaner, but didn't help at all.
5- I've searched for something weird installed on my PC in "Programs and Features" and also with the Revouninstaller, but didn't find anything.
6- My last resort was to use a Restore Point... After I restored the black borderlines weren't showing up, but after some time they started appearing... tried restoring 2 times, but the same thing happened.
Please Help me, I don't feel like formating my PC because of this crap. But if it persists I'll have too.