While most of us here prefer Google, Windows Live does have one great feature that Gmail doesn’t yet provide: a single-use security code that lets you login on a public computer without having your password stolen. Here’s how it works.

The security code actually works by hooking up your cell phone number into your account, and then signing in with a single-use security code sent to your phone as a text message—it only works once, so even if there’s a keylogger on the public computer it won’t matter.

Setup Your Account for Single-Use Codes

To get your account setup for using a single use code, you’ll need to head to this page, and then click on the “Windows Live Account overview” link—or you could head into your Windows Live Account overview screen if you can find it.

At this point you’ll want to check the Password reset information section, and then click on the “Add” link next to Mobile Phone.

Add in your mobile phone number and then click the Add button, which will send you an email verification.

Once you’ve verified that your account change is correct, you can proceed to actually using the feature.

Using the Single-Use Code on a Public PC

To use this feature, anytime you head to the Windows Live login page for any Windows Live service, you’ll be able to click the “Get a single use code to sign in with” link—if you don’t see this and instead see your username, click to login as another user first.

Then you’ll need to click the “Get one here” link next to “Don’t have a code?”.

Enter in your email address and phone number, and click the “Send text message” button.

Check your phone, because you should get a code very shortly after this.

And now you can use the code to login.

And there you are—now nobody can steal your password on a public PC, because the code will expire immediately after using it.