User Experience

• Versions of Windows from Windows 95 onwards have had search tools built into them; Windows Vista made a significant foray into searching more seamlessly. Windows 7 took search integration to an entirely different level of integration. While Windows Vista and earlier operating systems had users click on the "Start" menu and navigate through a series of nested menus to find programs, the Windows 7 "Start" menu is dominated by the Search box. This has removed several interface conventions that users have long taken for granted, like having all of the computer's hardware settings accessible through the Control Panel. Other work has been done to make it easier to avoid the "Start" menu entirely, like giving the users a row of launch icons across the bottom of the screen for commonly used project folders and applications.
  
  

Security Model

• Security is a mindset in computers and computer architecture. One of those deep mindset changes is different level of privileges for various categories of users. Significant improvements in security can be had by having the user spend the majority of his time in a standard user account, rather than spending his entire time in Administrator level accounts. Windows Vista did strong enforcement -- but also prompted the users for administrator level passwords dozens of times through a routine workday. Windows 7 significantly refines the process and reduces the number of times that the user sees the User Access Control panel.
  
  

Backwards Compatibility

• Microsoft's bread and butter in the Operating Systems market is making sure that applications that functioned on earlier versions of Windows work on current versions of Windows, but it's been far from perfect. Windows 2000 broke backwards compatibility with several Windows 95 architecture applications; Windows XP offered a better emulation environment. Windows Vista broke several Windows XP programs that were coded with the assumption that there would be routine administrator level access. Nevertheless, Windows 7 brings in virtualization technology from Microsoft's server architectures to better handle Windows XP legacy software.
  
  

Mobile Computing

• The laptop computer market has grown significantly since the release of Windows XP, and continues to grow, at the time of publication; Microsoft has worked extensively to take advantage of this increase in laptop sales. Windows 7 has several optimizations and tune-ups to help it come out of hibernation faster, and has improved power management for shutting down unused components on the computer to extend battery life.