An option to Vote-to-Close of "Is not about Windows Phone operating system" might be useful.
See this question as an example.
We could reword and generalise the close reason:
Questions about the Windows Mobile operating system are off-topic here as it is a completely separate platform from Windows Phone. See: Is Windows Mobile on-topic?
Perhaps something like:
Questions about general computing hardware and software are off-topic unless they directly involve tools related to connecting to Windows Phone devices. You may be able to get help on Super User.