SAN FRANCISCO -- The comeback story at Dell ( DELL) has a way of frustrating even as it inspires. The Round Rock, Texas, PC maker served up a prime example Thursday when it announced that it will sell notebook and desktop computers at Best Buy ( BBY), the No.1 electronics retailer in the U.S., a nice coup for Dell as it revamps its sales strategy. Unfortunately, Dell's timing is baffling, as its products will hit store shelves after Santa has left town. Dell said it will offer a variety of PCs at 900 Best Buy stores "in the next few weeks." But spokesperson Bob Kaufman acknowledged that the products will not be available at Best Buy until after Christmas. That's no trivial issue, as it means Dell will miss the holiday shopping frenzy in Best Buy stores. Last year, holiday sales accounted for 19.6% of all U.S. retail sales, according to the National Retail Federation. At Best Buy, U.S. sales in December accounted for 15.6% of the company's total revenue last year. Dell, which until recently sold exclusively through direct phone and Internet orders, has been actively increasing its retail exposure, striking a string of deals with stores around the globe in recent months. So Dell is better positioned than it ever was to rake in holiday shopping dollars this season.