Microsoft has been haunted for years by the ghost of Windows XP -- the 8-year-old operating system that many big businesses still view as good enough for their purposes and far less painful than upgrading to its successor, Windows Vista. More than 200,000 people supported InfoWorld's "Save Windows XP" campaign, and corporate tech buyers have mastered complex "downgrade rights" to stick with it.

Now, with the new Windows 7 available for large enterprises to use, the company's conversations with those customers are starting to sound like someone counseling a friend stuck in an unhealthy relationship: Get over it! There's something better out there for you!

That's the message Microsoft is delivering this morning -- releasing a big batch of case studies and research aimed at persuading its largest customers to move to the new version of its operating system.

The blitz is focused primarily on Microsoft's volume-licensing customers, who have the right to upgrade to new versions of software during the life of their contracts. Those customers are a big part of Microsoft's business, and the company wants them to renew their deals when their existing agreements expire. It's not an easy sell, given Windows Vista's repeated delays and disappointing tenure. Just last week, the Directions on Microsoft Research firm issued a new warning about the complexity of the volume-licensing agreements.

Microsoft is hoping that Windows 7 will help convince customers that there's still value in the deals.

"What we're really doing is saying, 'Hey, you own it. Deploy it, and get off of XP. Move on," said Gavriella Schuster, a Windows general manager, in an interview last week. "Throughout Vista what a lot of customers did is they brought new hardware into their environment and then they standardized back to XP. It's like, don't do that! Run a heterogenous environment for a bit, until you get everybody on 7, but you're going to save money when you get everybody to 7, so try to get there as soon as you can."

A big part of today's push is a new Forrester Consulting study -- commissioned by Microsoft -- that concludes that companies are very focused these days on cutting technology costs, supporting remote workers, boosting employee productivity and improving the overall level security of their information and networks. Microsoft is publicizing the findings to make the case for Windows 7's enterprise features. Some of them, including BranchCache and DirectAccess, work in conjunction with Microsoft's Windows Server 2008 R2 release.

More broadly, Microsoft is making the case that companies will be able to save money by using Windows 7, particularly with a new version of the Microsoft Desktop Optimization Pack, scheduled for release at the end of October.

Microsoft this morning is releasing a series of case studies from companies and organizations including the City of Miami and UK professional services firm Baker Tilly. The studies focus on areas including application deployment, IT help desk calls, unauthorized application installation, and power consumption. Overall, Microsoft says the case studies show that companies can save anywhere from $89 to $160 per year, per computer, in IT labor costs, or roughly 10 percent to 20 percent.

Windows 7 was made available to Microsoft's volume-licensing customers Aug. 7, and it's scheduled to be released to the public Oct. 22. Of course, there's always Windows 7's Windows XP Mode for anyone who just isn't ready for the big breakup.

Previously: Leaping from Windows XP to 7? Some important stuff to consider