User Account Control in Windows Vista

Windows XP had a major Achilles heel: by default, when you installed it you had administrator access. As an administrator you have total control over your system, which means you can change system settings, install software and make any modifications you wish. Unfortunately that administrative access was quickly exploited - if you're running in administrator mode and a bit of malicious software sneaks onto your system, it too has administrative access, which means it can cause chaos. If you've ever suffered from malware, for example when your PC blasts you with unwanted adverts even when you're not browsing the Net or your browser home page gets changed without your knowledge then you've seen the problem in action.

In Windows Vista, a new feature called User Access Control - UAC - solves the problem by preventing any system changes from happening without your knowledge. For example, if a program's attempting to change your Internet settings, a UAC message will pop up. You've then got a choice: you can say "continue" and accept the changes, or click "cancel" to prevent the changes from being made.

UAC works in two ways. If you're logged in as the computer administrator (which, as the owner of the PC, you probably will be), system changes no longer happen silently. Instead, the UAC warning will pop up and nothing will happen if you don't click Continue.

If you're not the computer administrator, UAC is more demanding. Instead of the Continue and Cancel buttons, you'll be asked for the administrator password. If you don't have it, the changes won't happen - even if you want them to. That means UAC doesn't just protect you from malicious software, but also from members of your family fiddling with your system settings.

QUICK CONFIRMATION

If you're logged in as the administrator and make changes to the system settings, User Account Control pops up a quick warning. It essentially says "are you sure you want to do this?" and if you want more information, clicking on the Details arrow tells you what changes are being made. Clicking on Continue gets rid of the warning and completes the task. Nine times out of ten you'll see this warning because of something you're doing, but the UAC warning will also pop up if software attempts to change your system settings.

SHOW YOUR CREDENTIALS

If you're not signed in to an administrator account, the User Account Control warnings look a bit different. You can't simply click on Continue to get rid of the warning - you need to provide a valid administrator password to continue. If you don't know the password - which, unless you're the administrator, you won't - then you won't be able to continue. It's an effective way of preventing other people from making a mess of your PC or installing things they shouldn't.

SILENCE IS GOLDEN

UAC is switched on by default, but in some cases - such as when you're the only user of your PC and you enjoy tweaking your system settings - you might find the warnings rather annoying. If you're sure you want to disable UAC, you can do it by launching Control Panel and then clicking User Accounts and Family Safety > User Accounts > Turn User Account Control on or off.

FINAL WARNING

You can now disable User Account Control by unchecking the tick box and then clicking on OK, but as you can see from our screenshot Microsoft does warn against it. We'd advise keeping UAC enabled unless you're 100% confident that your system is secure.