This week, Google unveiled a computer like no other: the Cr-48, a notebook that relies on the Web for all its software applications. Yet the Web search giant thinks the notebook can compete with computers that run all kinds of installed software. The matte black Cr-48 won't be sold to the public, but thousands are being sent to consumers and businesses who have volunteered to test it. It introduces a new kind of operating system, called Chrome OS, that turns to the Web for almost everything. Google is pitching Chrome OS as its vision for a new form of computing—one that shifts the data, functionality and almost everything else you would expect from your desktop computer into the cloud.