Microsoft announced a plan to give holiday-season computer buyers discounts on upgrades to its Vista operating system and new-generation Microsoft Office suite due out next year. The software giant's aim was to overcome reservations of shoppers inclined to strip their year-end gift lists of products based on soon-to-be outdated Microsoft software.

Microsoft missed the original delivery date this year for Vista, saying it needed more time to refine it.

Microsoft said it was collaborating with hardware makers to provide coupons guaranteeing holiday-season computer buyers "Express Upgrade" to Vista and Microsoft Office 2007.

The offer would apply to Windows Vista Capable personal computers that came installed with Windows XP or 2003 Microsoft Office. PCs loaded with Windows XP or pre-installed with 2003 Microsoft Office software can be upgraded via the Express Upgrade to Windows Vista and Microsoft Office Technology Guarantee program. Express Upgrade will be available to consumers and small businesses from 26 Oct 2006 through 15 March 2007.

"Our customers can shop for a new PC with confidence this holiday season because of the Express Upgrade to Windows Vista and Office Technology Guarantee programs," Microsoft vice president Mike Sievert said in a release.

"These programs ensure people will have a great experience with their Windows XP-based PCs today, and an even better one when Windows Vista and the 2007 Microsoft Office release become available."

Upgrades would be offered free of charge or at discounted prices depending on computer manufacturer, according to Microsoft.

So,. if you purchase a PC running Windows XP this holday, you should remember to take into account the upgrade path of the SKU you purchase. In the US, the upgrade path looks like this (but will vary by region):

Windows XP Media Center Edition 2005 --> Windows Vista Home Premium (nominal fee)

Windows XP Professional --> Windows Vista Business (nominal fee)

Windows XP Tablet PC Edition --> Windows Vista Business (nominal fee)

Windows XP Professional x64 Edition --> Windows Vista Business 64 (nominal fee)

Meanwhile, upgrades of this type:

Windows XP Home Edition --> Windows Vista Home Basic

Windows XP Home Edition --> Windows Vista Home Premium

Both will be available at 50% discount from the boxed product upgrade price, plus shipping and handling.