Dell on Friday extended sales of PCs equipped with Windows XP by a week, citing customer demand.

The computer maker will sell three XP-powered configurations of the Inspiron 530 desktop and one model of its XPS 630 desktop through the early hours of June 26, Dell announced on its US Web site late last week.

Dell touted "Extended by popular demand" on the page, and added that the deal will end at 5:59 a.m. US central time on Thursday.

Dell Australia will support XP on selected platforms until close-of-business this evening. Thereafter selected gaming lines, including XPS 630 desktops and XPS 1730 notebooks will participate in the XP downgrade rights programme, a company spokesperson said.

Previously, Dell had said it would shut down sales of Windows XP Home and Windows XP Professional on June 18, saying that it needed to stop taking orders then in order to meet Microsoft's requirement that it ship XP-equipped systems no later than June 30.

"We're offering select configurations through June 26," said Dell spokeswoman Anne Camden on Monday. "We're not offering any components or accessories on these systems that might cause a delay in shipping," she said when asked how Dell could change its last-sale date and still make the Microsoft-mandated deadline.

The Inspiron 530 and 530s, and XPS 630 can be configured by the user, however, with the usual customization tool, to, for example, substitute a faster processor, add more memory or change out the hard drive. The Inspiron desktops can be ordered with either Windows XP Home or XP Professional, although the latter costs US$20 extra.

After June 30, Dell and other major computer manufacturers, including Hewlett-Packard, Lenovo Group and Acer have said they will offer XP only as a downgrade when purchasing machines with a Vista Business or Vista Ultimate license. Only Windows XP Professional can be factory-installed as a Vista downgrade.

Downgrades will be done free of charge for customers buying most systems in Dell's small- and mid-sized business brands, the company has said, but it will charge up to US$50 for the factory installation on the entry-level Vostro desktops and laptops, and US$20 on the limited number of consumer-oriented models that will offer the option.

Dell isn't the only one to relax the rules on Windows XP. Microsoft itself has expanded the pool of hardware allowed to offer XP Home twice in the last two months. In April, it extended XP's availability until June 2010 for inexpensive subnotebooks; three weeks ago, it added low-cost desktops, dubbed "net-tops," to the mix.