For all the talk about the advantages of Windows 8 over Windows 7—for example, account sync, better multiple monitor support, and faster startup times—some people just can't get past Windows 8's radical shift in user interface. Some may even want to ditch Windows 8 altogether in favor of Windows 7 after spending a few days with the new OS.

In a Monday blog post, usability expert Jakob Nielsen of the Nielsen Norman Group explained in excruciating detail exactly why and how Windows 8 is difficult to use. It was a damning report that might have many questioning whether to take the Windows 8 plunge. The good news is you can buy a PC loaded with Windows 8 Pro, try out the new OS, and then downgrade to Windows 7. Unfortunately, however, the road back to Windows 7 can be confusing and full of twists.

Hewlett-Packard is typical: It does not support downgrades of consumer-grade Windows 8 PCs to Windows 7. But if you buy a machine loaded with Windows 8 Pro, you can make the jump. HP's policy is based on Microsoft's licensing terms, which support downgrade rights only to new PCs preloaded with Windows 8 Pro, the version of Windows designed for business.

[See related: 8 worst Windows 8 irritations (and how to fix them) ]

Unfortunately, machines loaded with Windows 8 Pro will demand a pricing premium over similarly spec'd Windows 8 systems. We ran a quick comparison survey of machines from HP, Dell, and Toshiba, and found that an upgrade to the Pro version of Windows 8 increased system prices anywhere between $35 and $100.

And even when the price delta is small enough to justify buying a Windows 8 Pro machine (complete with downgrade rights!), the downgrade process can still be difficult to figure out. When PCWorld researched this, sales and support reps for both Microsoft and major PC manufacturers told us two different stories.

A Dell representative said that to downgrade from Windows 8, you needed to buy a new, unused copy of Windows 7—thus making the whole point of having downgrade rights pointless. Another representative said a Windows 7 disc image would be built into new Windows 8 Pro machines. This contradicts pretty much everything Microsoft has ever posted online about downgrade rights.

But after scouring Microsoft's online support pages, checking out real-world downgrade experiences on various forums, and then confirming the process with Microsoft's press team, we can now share the truth about how downgrades work for anyone with a PC running Windows 8 Pro.

But first: Why downgrade?

Microsoft offers a downgrade path mostly for enterprise and small business PC users who may not be ready to use the new version of Windows. Some businesses don't want to suffer the training costs associated with rolling out a new OS to employee workstations. Others are concerned about incompatibility issues with legacy software.

Consumers, on the other hand, usually want to dump Windows 8 because they simply don't like the new OS. The Nielsen Norman Group found consumers' main gripe with Windows 8 is the dual nature of the system, which combines desktop and touch-friendly environments in an oftentimes confusing melange. Not only is the user interface inconsistent, it also requires users to remember where to go for which features, and to waste time switching between interfaces.

[See Related: Windows 8 interface called 'disappointing' by usability expert ]

You need to really want it

If you already know that you're going to downgrade to Windows 7, you could save yourself some grief and buy a new Windows 7 PC. First, just because you have the right to downgrade a Windows 8 Pro machine to Windows 7 doesn't mean running the older OS on newer hardware will be problem-free. HP, for example, warns that it hasn't tested all of its Windows 8 hardware with Windows 7. So the company says there's no guarantee you'll be able to download the drivers you need to run your Windows 7 system properly.

Second, even though Microsoft and its partners are pushing Windows 8, you can still find Windows 7 machines for sale on Amazon, Best Buy, and Dell, to name a few locations. Amazon, for example, is selling a limited number of 15.6-inch Samsung laptops featuring a 2.4 GHz Intel Core i3-2370M processor, 6GB RAM, a 750 GB HDD, and 64-bit Windows 7 Home Premium for $500.

Best Buy has a 14-inch Asus laptop with a 2.3Ghz Intel Pentium processor, 4GB RAM, a 320GB HDD, and 64-bit Windows 7 Home Premium for $300. You can find comparable Windows 8 machines for around $100 to $200 more. So you will also save a bit of money if you purchase a Windows 7 machine instead of Windows 8. Also, if you buy a Windows 7 machine before January 31, 2013, you have until February 28 to purchase a Windows 8 upgrade for $15.

Here's the bottom line taking pricing and installation headaches into consideration: As long as Windows 7 is available on new PCs, buying a Windows 8 Pro machine with downgrade rights really only makes sense if you plan on returning to Windows 8 at a later date. That way, you'll have hardware built for the new version of Windows such as a convertible laptop or an all-in-one desktop PC with a touchscreen.

It's also important to note that you cannot downgrade to Windows 7 after buying a Windows 8 Pro upgrade for an old Vista or Windows XP machine. Your only possible downgrade path in that situation is to reinstall the original OS that came with your PC, as long as you still have your old system discs that is.

Next Up: What can Windows 8 Pro downgrade to?