Microsoft has unexpectedly withdrawn its promotional pricing for Windows 7 - the software giant's latest desktop and laptop PC operating system - after demand so strong that its online store apparently crashed.
The online UK Microsoft Store now states "Promotional pricing no longer available".
Conspiracy theorists are sure now to question the supposed crash, hinting that Microsoft merely wanted to stop orders at the low rate.
Microsoft had been selling Windows 7 at Windows 7 Home Premium in the UK for £49.99, a 67% discount from the list price of £149.99, and selling Professional for £99.99, 55% under the usual £219.99.
Prices have now increased to £79.99 for Windows 7 Home Premium, £189.99 for Windows 7 Professional, and £199.99 for Windows 7 Ultimate.
Microsoft Windows 7 will be released on October 22, 2009.
At the initial discounted rate the Amazon UK store claimed that it had sold more copies of Windows 7 in the sale's first eight hours than it did in the 17-week run of a similar pre-order offer in 2006 for Windows Vista.
UK vendors taking part in the promotion were Amazon.co.uk, Argos, Comet, Currys, Dixons, Ebuyer.com, John Lewis Partnership, Littlewoods, Micro Anvika, PC World, Play.com, Staples and Tesco.
Amazon has fallen in line with Microsoft's new pricing, but Dixons remains at the lower rate. Its website states that the offer "will end August 9, 2009, or while supplies last".
European customers will receive Windows 7 in special editions, dubbed 'E' for 'Europe', that have been stripped of Internet Explorer 8 (IE8). A month ago, Microsoft decided to remove IE8 from Windows 7 in an effort to head off EU antitrust regulators, who may still force the company to take more drastic measures.