A Microsoft representative confirmed that users may buy an OEM copy of Windows Vista at a substantial discount, provided they adhere to the terms of the license—which, incidentally, may mean providing support for family members.

In addition, users should still be subject to the same familiar re-activation restrictions as users of a retail Vista license and Windows XP, a spokeswoman said. Users can alter the PC's hardware substantially, but they will be forced to reactivate—not repurchase the OEM software—if they do, she said.

One system builder pointed out, however, that Microsoft's OEM license forbids the software from being transferred to a whole new machine, from scratch, once it is installed on the original target machine.

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OEM copies of Vista began showing up this week at e-tailers like Newegg.com, for substantial discounts, which can run up to half off the price of a standalone retail copy of Microsoft's Windows Vista operating system. Microsoft is also offering its own in-house discounts, in the form of a Vista Family Pack, which allows the purchase of up to two copies of Vista Home Premium for $49.99, provided that a customer buy Windows Vista Ultimate at full price, through retail.

For those who don't need a full manual, however, the Windows Vista OEM versions offer substantial savings. Normally, such versions are restricted to "System Builders," not large corporations purchasing thousands or even hundreds of copies of the operating systems through Microsoft's volume licensing programs, but small mom-and-pop computer shops building individual systems for local communities. The license is agreed to when the shrinkwrap the package is sealed into is broken.

Read the full story on PCMag.com: Microsoft Answers 'Vista OEM' Questions