Microsoft’s User State Migration Tool
Upgrades and replacements are a part of PC life. Every two to four years, most of my friends find themselves with a new PC, copying all their files, recreating bookmarks and shortcuts. It’s a painful process, and data usually gets lost. E-mail and preferences are tucked away in hidden folders, and using the Export tools for each application can eat plenty of time. Microsoft has a tool to help you with those all-too-often transitions; the User State Migration Tool.
The current version, 3.0.1, is only for XP and Vista, but the 2.6 version will help transfer data from Windows 95 and later.