I won't waste time rehashing the argument over whether Windows Vista is any good. The fact remains that lots of people prefer Windows XP, and they'll go to great lengths to get it.

The problem: Windows XP "officially" went off the market on June 30, 2008, and computer vendors aren't supposed to sell new machines configured with any version of Windows except Vista.

Fortunately for XP enthusiasts and Vista vetoers, the PC marketplace still has a loophole or two in it. In response to pressure from customers, Microsoft has made some concessions for people who really want XP, offering a lifeline for users willing and able to wade through the company's convoluted downgrading program. The upshot is that virtually every copy of Vista Business or Vista Ultimate Edition is sold with a license for XP, which a computer manufacturer can exercise to install XP Professional on any Vista Business or Vista Ultimate PC.

But just because a manufacturer can install XP doesn't mean that it will. And just because its official policy permits it to sell XP machines doesn't mean that its employees understand that policy.

To find out how difficult it is to get a new XP machine these days, I asked the nine largest PC vendors in the United States--Dell, HP, Gateway, Toshiba, Acer, Fujitsu, Lenovo, Sony, and Asus--about the specifics of their downgrade policies. Then, to see how closely the official story synced up with the reality in the marketplace, I called sales representatives for each company and asked them whether I could purchase a new laptop equipped with XP from them.

The verdict? Downgrade policies are all over the map, and more than a few rank-and-file sales reps have a sketchy understanding of those policies. Some notebook PC sellers make getting XP preinstalled on a new laptop a snap; others don't offer it under any circumstance. As a rule of thumb, your odds of finding a machine with XP and a sales rep who knows how to configure a machine with that OS are far greater if you call the business sales line instead of the consumer sales line. (Be prepared to fib and say you're planning to buy 25 computers during the next 12 months.) Getting XP via online purchase can be tricky, too.

Here's how each manufacturer's formal policy--and informal reality--shakes out.

Dell

The Official Word: Dell has one of the most extensive and detailed policies on Windows XP of the nine vendors I investigated, but getting XP preinstalled on a machine may cost you extra. The company outlines the situation in this blog posting, where the company explains that though the XP downgrade program targets corporate customers, it's an option for general consumers, too. Though the rules are complicated, they are in line with those of most other sellers. To be eligible for an XP downgrade, you must be purchasing a Latitude laptop, an OptiPlex desktop, a Precision workstation, a Vostro laptop or desktop, an XPS 630 desktop, or an M1730 laptop. The machine must be specced to come with Vista Business or Vista Ultimate, and you can downgrade only to XP Professional. You must pay a $20 to $50 fee for the downgrade if you're buying a Vostro or XPS; corporate clients receive the downgrade at no charge. The program is slated to run until January 31, 2009, but Dell says that even after that it will continue to make some enterprise-level exceptions.

The Real Deal: Alas, not all Dell reps seemed to be up to speed on the company's XP strategy. First I tried to purchase an Inspiron running XP for "home use" (that's not covered in Dell's policy, but I decided to try my luck anyway). The harried sales rep I spoke to told me, "We don't have any computers running XP any more." After some pushing, he acknowledged that "I think business has them" but insisted that I'd have to check with another department to pursue such a purchase. He also repeatedly asserted that I could not obtain any machine in the XPS line configured with XP, contrary to Dell's posting. I called Dell's business sales line next and asked which computers I could get with XP. The rep casually (and correctly) answered "all of them," provided that I affirmed my intention to use the computer for business purposes. Of course, since Dell doesn't include models from the Inspiron line in its business sales category, the rep directed me to the Latitude series instead.

HP

The Official Word: HP offers dozens of computer models, but its policy regarding Windows XP breaks down fairly simply: None of its consumer products are eligible for downgrading, but all of its business products are. The machines covered include some(but not all) desktop PCs, notebook PCs, and workstations in the Compaq line, as well as some systems that bear the HP brand. On qualifying systems, HP will preinstall XP and you'll receive a disc for both XP and Vista. This arrangement will continue to be available until at least July 30, 2009, according to HP. Thereafter, HP will preinstall a customer's custom XP image on request.

The Real Deal: Visit HP.com and click through to one of the business sections (not to the Home & Home Office section), and you'll find that virtually every computer model listed has a clearly labeled XP option. When I called HP's sales operations, the reps largely repeated the official policy. When I asked a consumer sales specialist whether I could buy a new Pavilion laptop (a consumer model) with XP, she said no, but she referred me to some Compaq business models instead.

A degree of confusion erupted over the question of whether I would have to install XP myself: The first rep I spoke to told me that HP sold all of its machines with Vista preinstalled and that I wouldn't be able to get an XP disc until after I'd received the computer, placed a call to technical support, and asked for a disc to be mailed to me. Then I'd have to install it myself. ("Legally we can't do it," she said.) After nearly 20 minutes of talking and waiting on hold, I got transferred to a business sales rep who reversed the consumer rep, assuring me that XP came preinstalled on any machine labeled "Windows XP Professional custom installed" on HP's site and confirming that HP included a Vista install disc in the box as well.