The Windows 7 Family Pack, as the offering was called, has vanished from Microsoft's online store and is listed as sold out at major online retailers like Best Buy.
Microsoft did not issue a statement about why it decided to discontinue the offering, but its Web site makes it clear that Windows 7 Family Pack is now a thing of the past.
"Thank you for your interest in Windows 7. The Windows 7 Family Pack is now sold out through many of our partners. Please check our other offers," Microsoft said.
Because software can be reproduced in virtually limitless quantities, it's unlikely that Microsoft ran out of Windows 7 Family Packs in the traditional sense.
What's more likely is that the company is counting on holiday sales to boost software revenues and decided that the time was right to pull the offer.
Microsoft's Windows sales have suffered double-digit declines in recent quarters, so the company can ill-afford to leave any revenue on the table.
Windows 7 Family Pack was popular among budget-minded consumers, as it allowed them to save more than $200 on the purchase of three Windows 7 upgrade licenses.
Some third-party resellers are continuing to make Windows 7 Family Pack available through online outlets like eBay and Amazon, but the prices are now considerably higher than Microsoft's original price of $150.
Some Amazon sellers are offering Windows 7 Family Pack for more than $250.
What's not certain is whether the offerings are legitimate. Microsoft last week warned consumers about the growing amount of pirated software sold over the Internet, and filed lawsuits against several online software stores.
Microsoft formally launched Windows 7 on Oct. 22nd.
InformationWeek has published an indepth report on Windows 7. Download the report here (registration required).