As Microsoft Corp. prepares for the upcoming release of its Windows 7, Japanese manufacturers of personal computers are hoping the latest operating system will be the long-awaited silver bullet for a market hammered by eroding prices and flagging demand.

For the U.S. software giant, the success of Windows 7 will be critical to repairing a reputation bruised by its disfavored predecessor, Vista, especially at a time when Microsoft faces growing threats from rivals Google Inc. and Apple Inc.

The new operating system, now on sale only to large businesses, will be available to the wider public starting Thursday with expectations already hyped on the back of strong preorders.