Internet retailer Amazon.com has jumped the gun and started taking pre-orders for Microsoft's long delayed Windows Vista Operating system offering versions of the product from $100 to $399.

Although Microsoft has yet to announce a formal launch date or price for its OS, the online retailer has said that estimated on informal conversations with Microsoft and others in the computer industry it feels the date is the most likely.

Microsoft has repeatedly postponed the release of Windows Vista, which is already 5 years in the making. But they have in the past suggested that corporate customers would get copies in November while consumer customers would have to wait until the new year.

Vista will be sold in more versions than Microsoft's current Windows XP operating system, with different lines targeted at consumers and businesses.

The starting price will be $100 for Microsoft Windows Vista Home Basic Upgrade DVD-Rom going up to $399 for the company's top of the range Ultimate DVD-Rom version.

Amazon's UK store has as yet not followed suit.

It is not the first time Amazon has jumped the gun in an attempt to build pre-orders.

It allowed customers to order Sony's next generation PlayStation 3 console months before the company had even set a date or a price.