[A German translation of this article is available at faq-o-matic.net.]
The subtle differences between 32-bit and 64-bit Windows present so many intricacies and pitfalls that even Microsoft employees seem to have trouble getting it right. I just stumbled upon a KB article that describes how to reset the hosts file to its original state. The topic alone is funny enough - it is not as if the default hosts file contained great amounts of data. An entry for localhost (IPv4 and IPv6) is all you need, and on Windows 7 / Server 2008 R2 not even that. But anyhow, there seem to be enough people asking MS support for this or they would not have troubled with creating a package (ResetHOSTSFileBackToDefaults.MSI) that basically empties the hosts file.
