Windows 7 has only been available to pre-order since this morning, but it has already outsold Windows Vista during its 17 week-long pre-order period on Amazon's UK site.
The rush to buy the heavily discounted copies of Windows 7 took down Microsoft's site earlier today, but it's now working sporadically.
Amazon.co.uk is reporting a similar response, with Windows 7 unsurprisingly topping the online retailer's US software chart, and already selling more than Vista did in its pre-order period.
"Both Windows 7 upgrade packages shot to the top of the Amazon.com software bestsellers chart over in the US as soon as they were made available for pre-order at the end of June," said Chris Poad, director of software at Amazon.co.uk, in a statement.
"With the significant discount currently on offer, a similar level of high demand was expected in the UK for what is undoubtedly the biggest software release for many years."
The Home Premium version now appears to be sold out on Amazon.co.uk, but the Professional version is still available. Microsoft would not confirm how many copies of each would be on offer at the discounted price.
Click here to read our review of the Windows 7 beta.
