PC users don't have to wait until Windows 7 is officially launched later this month to get their hands on Microsoft's new operating system—it's already for sale on eBay, and at cut rate prices.

Windows 7 screen shot
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A copy of Windows 7 Ultimate was selling for $167.50 on Sunday, while a copy of the Professional version was going for $132.50. Numerous other eBay sellers are hawking other editions, at varying prices.

Officially, the full version of Windows 7 Professional is $299, with upgrades going for $199. Windows 7 Ultimate is priced at $319, with the upgrade version at $219. The full version of Windows 7 Home Premium is priced at $199, with an upgrade from Vista or XP costing $119.

Some sellers are pitching retail boxed versions of the software while others, the majority, are offering registration keys that allow users to activate a previously downloaded copy of Windows 7. Microsoft has already released Windows 7 to businesses, so it's possible the sellers obtained access to the software keys through their jobs or other professional contacts.

It's buyer beware, however. The software may lack Microsoft's official Certificate Of Authenticity and other piracy protection measures. So it's questionable whether purchasers will receive support for the product, or whether it will even run at all.

Under some circumstances, reselling software violates Microsoft's licensing terms and may also be illegal. The software maker has sued numerous eBay members in the past, accusing them of distributing pirated or counterfeited versions of its products.

Windows 7 officially goes on sale Oct. 22nd, with Microsoft planning a series of events and launch parties around the country.

Find out when Windows 7 will be right for your Enterprise. If you're weighing whether or not to migrate to Microsoft's new operating system, then be sure to check out InformationWeek's Virtual Event: Business Case For Windows 7. Click the link to register and immediately access an on-demand replay.

InformationWeek has published an indepth report on Windows 7. Download the report here (registration required).