Microsoft has launched its latest personal computer operating system – Windows 7.It is a vital release for the world’s biggest software company as it tries to strengthen its grip on the PC market and win back customers after the disappointing Vista. The new system – which is faster, less cluttered and has new touch-screen features – replaces Vista, which many home users and business customers said was too complex. John Mangelaars, Microsoft’s Regional Vice President Consumer & Online, admits Vista had problems: “When we started Vista, the development, we had a big vision and then we shipped a product where perhaps the vision was a little bit ahead of the product. Today, we really built a product with the consumers and based on their feedback. We feel like the product might actually be ahead of the perception.” Windows operating systems account for more than half of Microsoft’s profit and it hopes Windows 7 will grab back the impetus in new technology from rivals Apple and Google. Global PC sales rose 2.3 percent in the third quarter compared to a year ago, according to research firm IDC; that followed two quarters of declines.