NEW YORK — Microsoft released its own tablet computer for the first time when the new version of Windows came out Friday, as the software company tries to challenge Apple Inc. and its dominant iPad. The initial version of Surface will run a modified version of Windows 8 called RT. That means Surface won't run standard Windows programs, only apps designed for it and obtained through Microsoft's new online store. The device will start at $499, the same as the most recent, full-sized iPads. The display is 10.6 inches (26.9 centimeters) diagonally, slightly larger than the iPad's. The Surface went on sale Friday, though Microsoft started selling it at its store in New York's Times Square on Thursday. The only place to get them is at Microsoft's retail stores and its website. The earliest shipment for new online orders is now one to two weeks away. A Surface with Windows 8 Pro and the ability to run regular Windows programs will come a few months later. Microsoft hasn't disclosed the price. At the launch event Thursday, Microsoft described Surface as an extension of Windows, though the company noted that it's about extending other Microsoft products, too. Panos Panay, general manager of the Surface team, demonstrated watching movies and listening to music on the Surface. He also streamed audio and video from the Surface to a nearby Xbox. In a gimmick to demonstrate the tablet's durability, Panay dropped the device from shoulder height to the stage to show how tough its glass and magnesium case was. He also displayed a photo of Windows chief Steven Sinofsky standing on a Surface outfitted with wheels to make a skateboard. The Surface has a kickstand and its back camera is angled in such a way that when it's leaning on the stand, it shoots straight out, not toward the table. Panay demonstrated how that design allows someone to use Surface to take notes and record video at the same time. The cover for the Surface costs $100 extra for the basic, $499 device. It comes free with the $699 version. On the inside of the cover are printed “keys” for typing. Panay noted that the cover is pressure-sensing, so if you just rest your hands on it, it's not going to start erratically typing. The cover also folds back and can act as a support for the device's kickstand if you're placing it on your lap, although using it this way appeared to make it difficult to type. As previously disclosed, the Surface will come with fully functioning versions of Office 2013 software for word processing, spreadsheets and other business tasks. Other tablets running Windows RT, the lightweight version of the operating system, will also come with a version of Office for free. Is Surface a laptop or a tablet? “It's not just a tablet, but it's actually the best tablet I've ever used,” Windows chief Steven Sinofsky said. “It's not just a laptop, but it's the best laptop I've ever used.” Sinofsky said the Surface has twice the storage memory as competitors for the same price — though he didn't mention that about half of it gets taken up by the operating system and pre-loaded software. The Surface marks Microsoft's first venture into making computer devices, apart from the Xbox. — AP