copyright 2009, The Washington Post Windows 7 is no Windows Vista. But it remains a Windows operating system. That is, Microsoft's new release, arriving in stores and on new computers Thursday, ought to turn the troubled Vista into a bad memory. But it shouldn't make people forget about Apple's Mac OS X. The primary reward that 7 offers to Vista users who shell out for the upgrade -- $120 to go from Vista's Home Premium edition to 7 Home Premium -- is better performance. In particular, upgraders to 7 should see their computers win back some free memory (about 200 megabytes' worth, going by the figures in Windows' Task Manager tool on an HP and Dell laptop) and disk space (about 7 gigabytes even when upgraded to 7's overpriced Ultimate edition, the only kind provided by Microsoft's PR firm). Their computers may start up and shut down faster, although the HP took as long as ever to boot up. Windows 7 also disciplines Vista's most annoying feature, the 'User Account Control' dialog that asks you to confirm that you really want the computer to perform a given task, just in case a virus is trying to take over the system. You'll still get hit with a 'UAC' prompt when you install a program, but you should no longer see it during such routine actions as joining a new wireless network. On its desktop, 7 introduces a new, Mac-like version of the taskbar on the bottom of the screen. Here, the old rectangular taskbar buttons have been condensed to squares that can be rearranged and can point both to open programs and ones you use often -- much like Mac OS X's Dock. On a computer with enough graphics processing power to run 7's Aero graphics, each open program's taskbar button will also present a pop-up preview of its windows (or, in Microsoft's Internet Explorer browser, Web pages you have open in tabs inside its window). A right-click on these buttons brings up 'jump list' menus of frequently used commands. These changes combine to allow much more fluid switching between programs than in Vista, let alone XP. Another welcome shift comes at the far right end of the taskbar. Windows 7 sweeps the tray clear of meaningless icons left by third-party programs to show only such core system-status indicators as the volume control and a laptop's battery gauge. The Start menu, however, remains the same old mess, though that's also the fault of programmers who ignore Microsoft's software guidelines. But 7 takes a step back with its new Library folders, a set of prominent shortcuts to all the documents, music, pictures and videos on a computer. On a computer used by only one person who already sticks to the default Documents, Music, Pictures and Videos folders, they're more likely to confuse. Further confusion may result from Microsoft's decision to remove most of the applications it bundled with Windows Vista. This well-meaning effort to declutter the desktop excises a few programs nobody will miss, but others -- such as Windows Mail -- are widely used. Worse yet, Microsoft's suggested remedy of free, souped-up 'Windows Live' replacements (download.live.com) will introduce far more clutter: The Live installer comes preset to install everything from instant-messaging software to a video editor to a blogging tool to a browser toolbar. One Vista extra returns in improved form: its backup software, which now comes set to preserve all of a user's files and settings, not just a vaguely defined subset of them. But this program's inability to restore a selected program's data files -- say, e-mail archives -- to its original, hidden location in your user directory makes it useless in many common software malfunctions. On a new computer, Windows 7 should work well -- numerous third-party programs, such as Apple's iTunes and Google's Picasa, all worked just as they did in Vista. But upgrading an older machine from XP to 7 is a recipe for pain even if the computer meets 7's hardware requirements. Your first warning should be a flyer in the 7 box that begins 'Please read these instructions carefully and completely ...' -- as if it were the manual for a new circular saw. Microsoft calls an XP-to-7 upgrade a 'custom install,' but 'destructive install' is more accurate. You run an Easy Transfer utility to back up your files, the 7 installer wipes out XP, your programs and the drivers enabling your computer's hardware; Easy Transfer reloads your files and settings; you reinstall programs. On a test XP system, this left some applications missing their settings or files. But even if you're just moving from Vista to 7, things can go wrong. A Dell laptop wouldn't connect to a wireless network it had used reliably in Vista, while an HP laptop needed updates to its fingerprint-recognition and TV-viewing software -- and the latter update failed two times in a row. You might want to wait a month or so for your computer's manufacturer to ship a round of bug fixes. In other words, if you were hoping to stop policing random software-versus-hardware squabbles, Windows 7 isn't the operating system for you. Nor does it bring an end to drawn-out program installations and uninstallations, the risk of virus and malware attacks, the need to submit the computer to 'validation' checks, or compatibility problems between 32-bit software and 64-bit installations of Windows. Then again, for Vista users weary of that operating system's foibles, Win 7's selling points can stop at two words: 'not Vista.' 