You have a virus. Or worse, a rootkit.
Oh, come on, Laz - a rootkit?
It's just scumware, probably loaded into IE's extensions.
I saw a new scumware method a couple of weeks ago.
It loaded itself into Chrome's extensions, and when you removed it, it loaded ANOTHER extension, with similar properties (DANGER!!! Microsoft has detected REAL BAD STUFF on your computer! Call this weird 818 number!) but a DIFFERENT name.
The third time, I tracked it down to its own little folder in ProgramData (Win 8.1), uninstalled Chrome excised the ProgramData folder, and got a couple of mentions in the registry.
I re-installed Chrome, and we were good to go.
The persistence was interesting.