The last official day to purchase a new computer from Dell with Windows XP loaded was Wednesday, June 18th. Even so, the company is still making it possible to get a computer with Windows XP loaded, but customers will be expected to purchase a Vista license. the business and personal computing markets remain largely lukewarm in their reception of Windows Vista, Microsoft’s much maligned upgrade to Windows. Nonetheless, the tides are changing, and Microsoft annoucned that it will cease retail sales of Windows XP as of June 30th. OEMs (Original Equipment Manufacturers) will still be able pre-load computers with Windows XP. Support for Windows XP OEMs will continue through 2010.Dell’s offer allows them to take advantage of ‘downgrade rights’ built into Windows Vista Business and Windows Vista Ultimate licenses. Essentially, this allows the party purchasing the computer to choose an installation of Windows XP Pro instead of the Vista OS, with the option of returning to Vista at a later date. Customers who take advantage of this offer will receive their computers with Windows XP pre-installed, but bundled with a Vista installation disc.There’s more. In order to take advantage of the downgrade option Dell’s customers must first upgrade to one of the eligible versions of Vista (business or ultimate). In addition, this option comes free of charge only on Dell’s 630 and 720 H2C desktops, and the M1730 laptop. There are extra fees to downgrade the Latitude, Optiplex, Precision, and Vostro lines. Finally, Dell’s best-selling brand, the Inspiron, does not offer a pre-installed downgrade to XP. Customers purchasing these computers will have to manage the downgrade to XP themselves.What does this mean for you? Essentially, Microsoft is phasing out Windows XP in favor of Windows Vista. The older operating system will be supported for a while yet (until 2014), but the time to make the switch is coming. Given the high hardware and software demands of Vista, it may be best to wait until you’re ready to buy that new computer before making the switch.