Sentence:  What's needed is <WSD>defenestration</WSD> – throwing out the Windows mindset along with Microsoft's licenses and software – but that's not as simple as changing a boot CD or even migrating a whole raft of servers. What's involved is fundamental change both in how IT operates and in what it does. 
Meaning of the word marked with <WSD> tags:  The act of removing the (Microsoft Windows) operating system from a computer in order to install an alternative one.