Though, as already detailed, the system tray is significantly less cluttered, one icon you'll be seeing a lot of is the little flag with the red 'X' on it. This signifies one of the most important additions to Windows 7: the Action Center. This is the new hub for security and maintenance. It gives you a snapshot of how your PC is set up, any issues you might have and directs you to ways you can solve them.
For instance, since you've just installed Windows, you won't have any anti-virus installed and Action Center invites you to 'Find a program online'. Clicking this takes you to a Microsoft webpage with links to trusted AV software vendors' websites. Cunningly the order they appear is random, so no one can accuse Microsoft of favouring any particular package, not least its own Microsoft Security Essentials suite. This falls under the 'Security' tab that, when expanded, will show you the status of Windows' various security modules (Windows Firewall, UAC, Windows Defender etc.) and whether Windows reckons they're functioning correctly.
Under 'Maintenance', meanwhile, you can check for solutions to problems, updates and set up backups. Here you can also access the new 'Reliability Monitor' that tracks failures, warnings and keeps a record of changes made to your PC. This is an invaluable addition since it makes identifying the cause of problems so much easier. If system performance has recently slowed, you may be able to track this change to the installation of a specific piece of software or hardware, or even (heaven forbid) an update of some kind. Once you've identified the offending item you can then use System Restore, also accessible from the Action Center, to roll back to the point where you think your problems began. Vitally, these steps are well signposted, making it easier for relative novices to solve their own problems.
Another neat troubleshooting aid is the new Problems Steps Recorder. It's not so well advertised, presumably since you'll only need it when an 'expert' has asked to you use it, but it's an incredibly neat addition. Put simply it records what you do on your PC, allowing you demonstrate a problem you might encounter and how it comes about. You can also add comments as you go along and the final product is an HTML document with images, directions and comments all included. It's bound to be a godsend to tech support centres and long-suffering tech-savvy friends and family members alike. A passing mention must also go to the improved Resource Monitor, which also makes it easier to identify resource hogging applications.
Finally we come to the much maligned User Account Control (UAC). On Vista it was so irritating that it was the first thing we culled on any new PC, but in Windows 7 it's nothing like as obtrusive. Experienced users may still want to go without it, but it's less frustrating for novice users and the dimming screen effect can now be turned off if it has too great an effect on performance. In truth, though, that's less of a problem in Windows 7 anyway, so many will find the default settings just fine.