android.jpegwindows_8.jpegSAN FRANCISCO (AP) — Microsoft is scrambling to preserve what’s left of its kingdom. Since the company released its Windows operating system in 1985, most of the sequels have been variations on the same theme. Regardless of the software’s quality, Microsoft managed to remain at the center of the personal computing universe.

The stakes are much different as Microsoft Corp. puts the finishing touches on Windows 8 — perhaps the most important piece of software the Redmond, Wash., company has designed. The test or “beta” version of the revamped operating system currently being unveiled nudges Windows 8 a step closer to its anticipated mass market release in September or October.

PC MEETS MOBILE

Microsoft designed Windows 8 to help it perform a difficult balancing act. The company hopes to keep milking revenue from a PC market that appears to be past its prime, while trying to gain a stronger foothold in the more fertile field of mobile devices. It’s a booming market that, so far, has been defined and dominated by Apple Inc.’s trend-setting iPhone and iPad and Google Inc.’s ubiquitous Android software.

If Windows 8 is a hit, it could also help lift the fortunes of struggling PC makers, including Hewlett-Packard Co. and Dell Inc. Besides giving businesses and consumers a reason to consider new PC purchases, Windows 8 is expected to spawn a new breed of hybrid machines that will be part tablet computer, part laptop.

If Windows 8 is a flop, however? As Microsoft has stumbled, faster-innovating companies such as Apple and Google have elbowed their way into a position to steer the direction of computing for the next decade or two.

Microsoft badly wants a piece of the tablet market that has been cutting into PC sales since Apple introduced the iPad two years ago.

In the quarter that included the holiday shopping season, Apple shipped 15.4 million iPads, more than doubling the volume from the same time a year earlier.

Besides spurring more sales of the new operating system, Windows 8 is likely to drive demand for the next generation of the Office suite, another major moneymaker for Microsoft.

Windows 8 could inspire more PC makers to design machines that combine the convenience of tablets with the utility of a notebook computer. These devices would be similar to the so-called “ultrabook” computers that offer a Windows-based version of Apple’s lightweight MacBook Air machines.

GAME-CHANGER?

Whatever headlines Windows 8 grabs are likely to be quickly overshadowed next week when Apple is expected to show off the third version of the iPad.

Meanwhile, Google says more than 300 million smartphones and tablets are already running on its Android software, with another 850,000 devices getting activated each day.

At that rate, another 155 million to 180 million devices could be running on Android by the time Windows 8 comes out. As it is, a version of Android is already running the second hottest-selling tablet, Amazon.com Inc.’s Kindle Fire.

“Microsoft is late to the game and this is a different game than they have been playing,” one analyst said. “But if they hit a home run with Windows 8, it could still turn some things around.”