Microsoft may be preparing to discontinue sales of Windows XP, but some OEMs have found a way to circumvent the software giant's June 30 deadline. In yet another sign of the market's resistance to Windows Vista, Dell Computer, Hewlett Packard, and Sony on Wednesday all confirmed plans to exercise the downgrade rights Microsoft offers with OEM versions of Windows Vista Business and Vista Ultimate in order to continue offering XP-equipped PCs to their customers. Downgrade rights, which Microsoft also offers to volume licensing customers, give users the ability to roll back to the previous version of the product they're using. Downgrade rights have existed since 2001 for Windows, but many Microsoft partners say they've been seeing a recent uptick in the number of customers exercising downgrade rights to roll Vista back to XP Professional.