It's important to understand the phrase that appears just under each person's name. On your own personal PC, the word Administrator probably appears underneath yours.

Because you're the person who installed Vista, the PC assumes that you're one of its administratorsthe technical wizards who will be in charge of it. You're the teacher, the parent, the resident guru. You're the one who will maintain this PC and who will be permitted to make system-wide changes to it.

You'll find settings all over Windows (and all over this book) that only people with Administrator accounts can change. For example, only an administrator is allowed to:

• Create or delete accounts and passwords on the PC.

• Install new programs (and certain hardware components).

• Make changes to certain Control Panel programs that are off limits to non-administrators.

• See and manipulate any file on the machine.

There's another kind of account, too, for people who don't have to make those kinds of changes: the Standard account.

Now, until Vista came along, people doled out Administrator accounts pretty freely. You know: the parents got Administrator accounts, the kids got Standard ones.

The trouble is, an Administrator account itself is a kind of security hole. Any time you're logged in with this kind of account, any nasty software you may have caught from the Internet is also, in effect, logged inand can make changes to important underlying settings on your PC, just the way a human administrator can.

Put another way: If a Standard account holder manages to download a computer virus, its infection will be confined to his account. If an administrator catches a virus, on the other hand, every file on the machine is at risk.

In Vista, therefore, Microsoft recommends that everyone use Standard accountseven you, the wise master and owner of the computer!

So how are you supposed to make important Control Panel changes, install new programs, and so on?

That's gotten a lot easier in Vista. Using a Standard account no longer means that you can't make important changes. In fact, you can do just about everything on the PC that an Administrator account canif you know the name and password of a true Administrator account.

Whenever you try to make a big change, you're asked to authenticate yourself. As described on page 191, that means supplying an Administrator account's name and password, even though you, the currently logged-in person, are a lowly Standard account holder.

The idea is that if you really are a Standard account holder, you can call over an Administrator to approve the change you're making. And if you really are the PC's owner, you know the Administrator account's password anyway, so it's no big deal.

Now, making broad changes to a PC when you're an Administrator still presents you with those "prove yourself worthy" authentication dialog boxes. The only difference is that you, the Administrator, can click Continue to bypass them, rather than having to type in a name and password.

You'll have to weigh this security/convenience tradeoff. But you've been warned: the least vulnerable PC is one where everyone uses Standard accounts.