I wrote a simple, step-by-step guide for upgrading to Windows 7 from Windows XP on Dummies.com. Check it out if you’re considering upgrading a Windows XP computer to Microsoft’s latest operating system, Windows 7.

People with Administrator or Limited accounts usually have no problem connecting to the Internet through a dial-up modem. But when Guest account users sit down at that same computer and try to connect to the Internet, Windows XP, Vista and Windows 7 refuses to let them. What gives?

It’s a security measure built-in to Windows, unfortunately, and it works like this: The Guest account can use an existing connection to connect to the Internet. But Windows’ security restrictions forbid Guest account users from starting or disconnecting an Internet connection.

This problem doesn’t affect every computer. If you access the Internet through a cable or DSL account, for instance, your Internet connection is always “turned on,” even if it’s not being currently accessed. That lets Guest account users surf the Web without problem.

Guest account users accessing the Internet through a wired networked computer usually won’t have a problem. But if you have a wireless network connection, log on with another account to make sure the wireless link is up and running; some wireless accounts go dormant if unused, leaving the Guest account unable to reconnect.

But if you access the Internet through a dial-up modem, your baby sitter won’t be able to log on through the Guest account to check for e-mail.

There’s a solution for Windows XP, but it’s a bit awkward. First, download and run this program from Kelly’s Korner Web site. You only need to run that program once. Then, follow these steps when you want to allow the Guest account to access the Internet:

1. Enable “Fast User Switching” on Windows XP.
2. Connect to the Internet using your Administrator or Limited account.
3. Use Fast User Switching to log onto the Guest account.

Fast User Switching is described in pages 248-249 of Windows XP For Dummies.

The most awkward problem with this solution? Most dial-up Internet Service Providers usually drop the connection if it hasn’t been used for a certain amount of time. Unless your babysitter stays in front of your computer soon after you leave, your ISP will disconnect your connection.

But if your kids log on through the Guest account and you’ll be home to reconnect to the Internet if necessary, this might be the only solution you need.

Both Windows XP Home and Professional include a program to send and receive faxes, but the program’s hidden: It’s not normally installed when you install or upgrade to Windows XP.

After installing the fax program, it’s no problem to leave the fax turned on all day. Sure, the junk faxes still pour in. But I just click on their names and press the Del key: No more wasted fax paper!

You need four things to send or receive faxes with Windows XP: Click to read more »

When talking about computer security, the answer always depends on your personal level of paranoia: No computer system is completely secure. Many people are satisfied with Windows XP’s built-in “one-way” firewall. It makes a fairly decent effort to keep people on the outside from getting into your computer.

Other firewalls, such as ZoneAlarm, work as a “two-way” firewall. They not only stop people from breaking in, but keep programs from breaking out: They alert you whenever a program in your computer tries to make contact with the Internet. Who cares?

Well, some people write viruses or “stealth” programs that run unnoticed in the background, sending information from your computer to the Internet. For instance, a “backdoor” program could silently copy all your keystrokes and send them to somebody else’s computer over the Internet. That person could then analyze your keystrokes for your credit card numbers, passwords, and other personal material.

Some viruses contain built-in mailing programs that mail a copy of themselves to everybody in your address book.

Since these connections start from inside your computer, Windows XP’s firewall wouldn’t catch them. It lets *any* program inside your computer connect to the Internet whenever it wants. But a two-way firewall alerts you whenever any of your programs start an Internet connection, letting you authorize or refuse the connection.

“Two way” firewalls are much more difficult to set up than Windows XP’s built-in “one-way” firewall. Windows XP and third-party programs connect to the Internet quite often; it’s not uncommon to have more than a dozen Internet connections taking place simultaneously. With a two-way firewall, it’s up to you to figure out which programs are legitimate or not. But if you want more complete control over your computer and its Internet connections, a two-way firewall might better serve your needs.

I’ve turned off Windows XP’s built-in firewall and use the two-way firewall, ZoneAlarm Pro.

I cover Windows’ built-in firewall in my books Windows XP For Dummies, Windows Vista For Dummies, and Windows 7 For Dummies. But if you ever need to turn on the firewall or make sure that it’s turned on and protecting your PC, follow these steps: Click to read more »