H-P on Wednesday unveiled a “netbook,” a miniature laptop that costs $399. The announcement makes it the latest company to widely sell smaller, cheaper – and less powerful – PCs. An H-P netbook For years, success in the PC world was measured in improvements in storage and processing power. But several computer makers late last year introduced netbooks, which were initially aimed at people who couldn’t afford conventional computers. These computers have taken off like wildfire. They emerged too late to make a dent in last year’s sales figures, but netbook sales should reach 10.8 million in 2008,