I know its hard to believe this. But you can try doing this from your side and respond here back again.
I can't speak for Robert, but I've installed and run pgAdmin literally hundreds of times on Windows, Mac, and Linux, and have never seen it even crash a whole machine, let alone render one unbootable. We also probably have hundreds of thousands of users on Windows (based on the number of downloads we get), and have never had such a problem reported.