Leaked screenshots surfaced of setup screens of what appears to be a stripped-down version of Windows 8.1 that only includes IE and Microsoft's cloud services. Now hold it right there: If you're going to strip down an OS to just a browser, the LAST one you're EVER going to want to cripple down to that level is Windows. Why? It's a malware writer's paradise!
The reason why Chromebooks cannot get viruses at all is due to the military-grade security built into them: The root volume is read-only and write-protected. Packaged apps and Chrome extensions are jailed to their own chroots. The browser, and by extension all Web apps, is also chroot-jailed. On top of that, user sandboxes are also extended to this chroot-grade level of security: Even administrators (AKA owners) cannot see what other users have on their accounts. With good reason, of course: If a malicious app or extension makes it to one user account, it is confined and won't spread to the whole Chromebook.
In contrast, Windows by design is completely vulnerable. It's been a target for years on end. A browser-based version, obviously, wouldn't be any different. Even with UEFI, Windows PCs can still get infected, and even if Microsoft uses UEFI to copy Google's security model, guess what command you won't find ANYWHERE on a Windows machine, even in the C-prompt? Chroot! Which makes the military-grade sandboxing that Chrome OS users know and love virtually impossible on ANY Windows machine.
On top of that, Windows is SLOOOW by design. Even if Microsoft manages to strip down much of Windows 8.1's userland, the OS would be useless if Microsoft doesn't also strip down the core services bloat, and I'm pretty sure we all know why: because booting a Chromebook and Bingbook side-by-side, one would notice that the Chromebook would boot many orders of magnitude faster.
Using Gentoo Linux as the base, Chrome OS can indeed take advantage of technologies that make it extremely easy to trim down Linux's core bloat. In the case of Windows, guess what? The kernel would need to be completely rewritten! Heck, with the GUI and kernel as one (something I believe Mac OS X also does, but OS X happens to be confined to one brand of only powerful hardware to begin with, and thus impossible to benchmark on anything else), there's no way Windows on any machine — even one with an SSD — can possibly boot in 7 seconds. It's just not possible.
So, that's two flaws that prove The Chromebook Guys right about this concept being a failure in the making. Microsoft's track record certainly is not good when it comes to competing and one-upping competitors, that's for sure, and the only reason Windows and Office are any good is that they have network effects associated with them. MSN, Windows Live, Bing... Notice how they all NEVER managed to be a threat to Google? Well, based on these two flaws — malware and slow boot — neither will a Windows-based half-baked implementation of a Chromebook, not in a million years.