Notebook PC sales continued surging in the first quarter, with worldwide shipments up 35 percent from a year earlier, according to DisplaySearch data. Apple, continuing to gain ground, became the seventh-largest shipper of laptops, rising from the eighth-place ranking it had held for about a year. Apple was one of four companies that actually shipped more notebooks in the first quarter than in the fourth quarter of last year. Portable PC sales typically fall in the first quarter after the holiday-pumped fourth quarter. Toshiba, Dell, and Samsung also saw sales rise over the previous quarter. Hewlett-Packard remained the sales leader, a position it has held for seven quarters, with a 20 percent market share. With consumers increasingly gravitating to portable devices, notebooks already account for more than half of total PC sales.