The main problem here is that many companies and ISVs coded their Web applications for IE6, which is a non- standard browser. Thus, many apps custom built for IE6 will not run on the more Web standards-friendly Firefox and Chrome browsers as well as IE8, the browser that comes loaded on Windows 7. Organizations running IE6 surveyed by Gartner reveal that 40 percent of their custom-built Web applications will not run on IE8.

Despite warnings, companies are clinging to IE6 for a variety of reasons, states the Gartner report, including: the desire to minimize costs in a sour economy; ISV requirements that apps be IE6 specific; limited migrations to Windows Vista, which would have required a move to IE7.

In short, organizations did not factor the time-consuming task of inventorying and fixing IE6 applications into their Windows 7 migration plans. Gartner estimates that through 2014, when all support for Windows XP ends, IE8 compatibility problems will cause 20 percent of organizations to run overtime or overbudget on Windows 7 migrations.

So companies face a choice: Either spend time and money to upgrade IE6 applications so that they work in newer browsers, or keep running Windows XP.

[ For complete coverage on Microsoft's Windows 7 operating system -- including hands-on reviews, video tutorials and advice on enterprise rollouts -- see CIO.com's . ]