Microsoft Corp. (MSFT.O: Quote, Profile, Research) this week will begin a coupon program for personal computer buyers to upgrade to the new Vista operating system when it premiers next year in an effort to avoid a drop-off in PC sales over the holidays and ahead of the software's release.

Microsoft said on Tuesday the upgrade program will begin on October 26 for its much-anticipated Windows Vista operating system and Office 2007 software suite.

The program allows customers who buy a PC running Windows XP to still be able to upgrade to Windows Vista when the new operating system becomes available in early 2007. A similar program is in place for Office 2007, also due out early next year to consumers.
Most large PC manufacturers, including industry leaders Hewlett-Packard Co. and Dell Inc. will participate in the upgrade program, although upgrade offers may vary depending on the company.

The Windows Vista upgrade may be free or sold at a discount depending on the manufacturer, Microsoft added.