A Chromebook running office-style productivity tools. Image source: Google.

Here we go. Microsoft (MSFT -1.96%) won't walk away from the end of the Windows XP era unscathed -- at least not if Google (GOOG -1.80%) (GOOGL -1.82%) has a say in it. And Google has enlisted longtime Microsoft partners Citrix Systems (CTXS) and VMware (VMW) to help with the heavy lifting.

Yesterday was the last day of official XP support, with the final round of security updates for the 13-year-old platform. It was also the start of a big discount program on Google Chromebook computers, aimed specifically at the enterprise market.

Say goodbye to Windows XP.

The promotion makes sense because Windows XP is not exclusively tied to Luddites and tech-averse grandmas who just don't need anything fancier for their basic email and Web browsing needs. Many enterprise environments are handcuffed to XP, sometimes even locked down to the long-since unsupported Internet Explorer 6 browser that shipped with the original Windows XP. Business applications have been built to depend on quirks and bugs unique to the platform, and many others simply never got tested and qualified to run on anything else.

But now, it's high time to update those graybeard applications, qualify their functionality on modern platforms, and leave XP behind.

This is what Microsoft would like you to install instead.

Microsoft would love for IT managers to simply adopt a newer Windows version, and ideally Windows 8.1, which got a mandatory set of security and feature updates yesterday. I'm told that the new version moves away from the hard-nosed touchscreen focus a little bit, making it more familiar and usable for people with many years of XP-style experience. This could be a huge upgrade moment in the history of Windows.

But, like I said, Google won't let Microsoft have all the fun.

"It's time for a real change, rather than more of the same," Google says, complete with a link to Microsoft's Windows 8 upgrade program. Big G now offers $100 off each Chromebook system that's bought through the company's sales channels for business-class customers.

Google didn't forget about the need to run legacy Windows applications, which you cannot do on a plain Chromebook and its Linux-based innards. The discount jumps to $200 for Chromebooks with VMware's Horizon Desktop as a Service (also known as DaaS) pre-installed. Or, you can get a 25% discount on Citrix Systems' XenApp DaaS solution, which works out to roughly $50 per system.

...but Google has another option in mind. Image source: Google.

VMware and Citrix are happy to support this sale, because a significant non-Windows business platform would be good for their Windows-based desktop and app-sharing solutions. Doesn't really matter if it's Google's systems that break through, or some other desktop and laptop player with a big appetite. It could even be a neutered, low-cost Windows platform for all Citrix and VMware care. The key is to have low-powered systems in the hands of large business-class populations, with a need to deliver Windows-based apps to them. And Chromebooks fit that bill.

Now, it wouldn't make sense for consumers to buy Chromebooks via Google's enterprise program. There's a $150 fee for each computer to cover a centralized management system, which gives IT managers a way to manage lots and lots of Chromebooks in one simple interface. But it costs $50 more than the $100 discount, and really doesn't do much for one or two computers in private use.

So this promotion is strictly for business buyers. If there's a consumer-level discount program up Google's sleeve, the company hasn't cracked its poker face yet. Stay tuned.

If it's time to update your systems anyway, then why not jump to a totally different platform standard? It remains to be seen whether Google Chromebooks can carve out a significant space in the business sector. But you can't win the lottery without buying a ticket. On that note, this opportunistic promotion might give Google a foot in the door to Microsoft's most cherished market -- the business world.