Hewlett-Packard ( HPQ) grabbed the top place in PCs from Dell ( DELL) two years ago by jumping on the notebook bandwagon as consumers went shopping for desktop power in portable devices. Hewlett-Packard hopes to cash in again in an emerging category of hybrid laptops called super netbooks. The numbers. One of the most-watched devices in this category is the DM3, a 13-inch, thin, lightweight notebook with an eight-hour battery life, four-gigabyte memory and no DVD drive. HEWLETT-PACKARD introduced the DM3 in July priced at $599. On Friday it will sell on Amazon ( AMZN) for $499. The stock. Hewlett-Packard branched into IT services last year and hopes to get a chunk of Cisco's ( CSCO) networking market with the pending acquisition of 3Com ( COMS). But computers are still its biggest business and if hybrid notebooks are a winning category, Hewlett-Packard could continue to punish Dell.