Ok, let's start at the beginning..... where did you find this file?
A clean install would be creation of install media, formatting the dirve & reinstalling - resetting to defaults does not accomplish the same thing, no.
Again though, lets start at the beginning. A clean OS install is generally a last resort.
As AVScanner is a common one, we shouldn't have to resort to that.
Do you have any other anti-virus installed? AVG/Avast/Avira etc?