Microsoft is to offer Windows 7 at a discount to compensate for the fact that European customers will not be able to purchase an upgrade version of the new operating system. Further discounts will be available for those prepared to pre-order Windows 7 ahead of its release date.

The software giant today detailed its retail prices for Windows 7, due for release on 22 October. The full price UK shoppers will pay is £149.99 for Windows 7 Home Premium, £219.99 for Windows 7 Professional, and £299.99 for Windows 7 Ultimate.

However, for those willing to pre-order, Microsoft said that the Home Premium and Professional versions will be available for a "substantial discount" at £49.99 and £99.99 respectively.

"We want to reward those who've shown an interest in the product all along by giving users the right to order before the launch, and we will make sure suppliers deliver it," said Windows product manager Laurence Painell.

Customers interested in pre-ordering should go through the Windows 7 web site for now, but Microsoft said that buyers will soon also be able to pre-order through retail outlets and partners.

Following the launch, European customers will still be able to get Windows 7 at a discount, to make up for the fact that an upgrade version will not be available in Europe. This is a result of Microsoft's decision earlier this month not to include Internet Explorer with Windows 7 in Europe, because of its ongoing antitrust spat with the European Commission.

From launch until the end of the year, UK buyers will thus be able to purchase Home Premium for £79.99, Professional for £189.99 and Ultimate for £199.99.

"With previous Windows releases we had an upgrade product, but as we can't offer this with Windows 7, we want to offer users the opportunity to get the full product at an upgrade price," said Painell.

While these versions will still come without a browser, Painell said that Microsoft is looking at ways of ensuring that buyers who want Internet Explorer 8 are able to get it. Options being considered include putting it on a separate CD or USB memory stick for retailers to hand to buyers who request it.

Microsoft is also putting an upgrade programme in place for buyers who purchase a new computer between now and the Windows 7 launch. Painell said that customers buying a system with Vista Home Premium, Vista Business or Vista Ultimate will be able to get the corresponding edition of Windows 7 at no cost or for a small fee, depending on the vendor.