It's amazing what the threat of extinction can do. Just look at Microsoft Office 2007.

The productivity suite has been, along with Windows, the company's top cash cow for more than a decade. But now it is embattled. One problem is that there are free alternatives - Web-based software from Google and open-source software such as OpenOffice. However, the bigger problem is that it has been years since there last was a compelling reason to upgrade to a new version of Office.

Office 2007 attempts to reverse that.

When you launch the core applications such as Word, Excel, or PowerPoint, you will see a brand-new user interface. Gone are the multiple menus and toolbars of the past, replaced by a mega-toolbar Microsoft calls the "ribbon." What appears to be a menu no longer opens up the familiar lists of tasks, but instead changes the composition of the ribbon. For example, click on "Insert" and you get tools for adding graphics, links, tables, other files, and so on. The ribbon also changes composition automatically when you are working with such things as pictures and tables.

After you get over your "What have they done?" shock, the next thing you will notice is that in Word your default font is no longer Times New Roman, as has been the case throughout Word for Windows's existence. Instead a more contemporary sans serif font (Calibri) is now standard. And if you make use of Word's formatting styles, you will also see that they now make use of different colors rather than sticking to black and white.

The font change in its way is just as indicative of the changes in Office as the ribbon. The new version is intended to make it easier for users to produce better-looking documents, reflecting modern design trends.

"Easier," I hasten to point out, really means "easier once you have learned it." Expect to scream in frustration at your computer until you get the hang of Office 2007.

To me the biggest news in Office is that Microsoft has at last hired graphics designers with good taste. Further, the new interface makes tools to modify those nice new designs readily accessible. Whereas the templates included with Office used to pretty much lock you into their blueprint, Office 2007 templates are just a starting point. Color schemes, font choices, style options, and other design elements all can be changed by a couple of clicks. Like a template, but want its predominant color to be blue instead of red? Just click "Page Layout" to bring up that ribbon array and click on the "Theme Color" button.

Even Excel - where nobody typically worries about aesthetics - lets users create attractive (and also more understandable) spreadsheets. The change is most drastic, however, in PowerPoint. Those garish slide templates that you would never, ever use in a serious business presentation have been replaced by highly professional designs. Outlook, the e-mail and organizer program, is the least changed part of Office 2007, and the new touches there are mainly limited to composing e-mail messages.

One tip: If you get Office 2007, pay an immediate visit to the Office Web site (office.microsoft.com) and download the free utility to save your files as PDF (Adobe Acrobat). Because of a licensing dispute between Microsoft and Adobe, PDF support has been relegated to an add-in rather than a built-in.

I tested Office 2007 on the same Dell Inspiron E1705 laptop and HP Pavilion m7680n desktop I used to test Windows Vista, and performance was zippy. I saw no sign that all the new features in Office would add sluggishness to a typical PC. Note, however, that Vista is not required for Office 2007. Microsoft would like you to think that and released the two products at the same time for marketing purposes. But Office 2007 will run fine on Windows XP.

My biggest complaint with Office is the way the company has divvied up its various versions. Most individual users would want the Home and Student Edition, which costs less than other versions and allows installation on more computers. But the company has stripped Outlook (which was in the comparable Office 2003 edition) from the bundle. You therefore need to either buy Outlook separately (about $95) or step up to the more expensive Standard or Small Business editions. That amounts to a $130 hit if you are buying Office with a new PC; $210 if buying at retail.

The other Office 2007 concern is its new file formats. These allow the design features to work and have smaller file sizes than the old ones. But older versions of Office can't read the new formats unless users install a conversion package. If you are going to share your documents with other users, you should save a copy in the old format to ensure compatibility. Because you surely don't want to create an impressive-looking document that nobody else can read.