Leave it up to the security community to figure out that a simple registry key which identifies the POSReady 2009 operating system could be hacked into the registry of a WindowsXP machine to keep it getting updates. Well ... sort of. This is where it gets weird. Read this ZDNet article with Microsoft's response carefully... and notice that while they admit this will update WindowsXP systems, there is a string of caveats that should make you think twice.
It's important to acknowledge that this hack (and that's all this really is) essentially tricks the update service into thinking your OS is a point-of-sales WindowsXP embedded device. The essential questions, which Microsoft hints at, is just how different is WindowsXP from WindowsXP Embedded? The answer is - quite a bit, actually. Check out this paper on the difference between WindowsXP Professional and WindowsXP Embedded and decide for yourself if you're willing to take that risk. Architecturally, the two operating systems are close, obviously since they're both based off the same kernel. Once you start getting into the add-ons and run-time environment options Professional and Embedded start to look dramatically different - in my opinion. This means that if you start applying patches and bits meant for the embedded operations system onto your corporate desktops at very least the results would be unpredictable...
So let's summarize my thoughts here.
- some organizations are still on WinXP on the corporate desktop (and elsewhere, obviously)
- for those that haven't migrated, excuses are critical... not necessarily valid, but critical
- a quick registry hack is available which tricks Windows Update into pushing patches and updates meant for a variation of your WindowsXP operating system onto your machine(s)
- potentially de-stabilizes your WindowsXP operating system
- necessitates significantly more testing to ensure compatibility
- quite obviously breaks your software agreement
- could potentially get you into a CFAA or other legal situation
Folks - this isn't a viable work-around to keep WindowsXP alive. It's a bad, bad idea.