Chatting with friends and family this season with an instant messenger program? You might see an IM offering free shipping on holiday gifts or a link to an electronic greeting card.

Think before you click that link. Many instant messenger viruses, worms, and Trojans are spread when someone clicks a link or opens an attachment in an infected instant message.

To recognize social engineering attacks and help protect yourself from these threats, see 5 steps to help avoid instant message viruses and What is social engineering?

Also, follow our general home computer safety guidelines, which you can find at Microsoft Security at Home and which include the following:

1. Keep your firewall turned on.

2. Keep your operating system and your IM software up-to-date.

3. Use antivirus software.

4. Use antispyware software.

A reader asks:

Is Windows Defender built into Windows Live OneCare? Or do I have to download Windows Defender separately?

Windows Defender is built into Windows Live OneCare. If you use Windows Live OneCare, you do not have to download Windows Defender.

What is Windows Defender?

Windows Defender is a free program that helps protect your computer against pop-ups, slow performance, and security threats caused by spyware and other unwanted software. For more information, see Windows Defender: Spyware protection for free.

What is Windows Live OneCare?

Windows Live OneCare is a comprehensive service that helps protect your computer from many different kinds of threats. It also helps you back up your important documents in case of emergency and runs regular tune-ups to help your computer run smoothly. For more information, see 5 Reasons to use Windows Live OneCare to help protect your computer.

If you have questions, click the EMAIL link above to contact us. Then check back soon to find out if we've answered your question here.

One of the most important rules in computer security is Don't open e-mail attachments.

But recently, we've seen more malicious links in e-mail messages. These links might look genuine, but they could be forged.

Here are some tips to help you make the most of your e-mail without compromising security.

Don't trust the sender information in an e-mail message
Even if the e-mail message appears to come from a sender that you know and trust, use the same precautions that you would use with any other e-mail message.

Fraudsters can easily spoof the identity information in an e-mail message.

Read before you click

A link in an e-mail message might promise to take you to site A, but will actually take you to site B.

Most e-mail programs (such as Outlook 2007) show you the real target address, or URL, of a link when you hover the mouse over the link.

Before you click a link, make sure to read the target address. If the e-mail message appears to come from your bank, but the target address is just a meaningless series of numbers, do not click the link.

Make sure that the spelling of words in the link matches what you expect. Fraudsters often use URLs with typos in them that are easy to overlook, such as "micosoft." For more tips, see Recognize phishing scams and fraudulent e-mails.

Verify the identity of the site

Some sites feature verified identity information. When you visit a verified site using Internet Explorer 7, the browser address bar turns green and the identity information appears on the right-hand side of the address bar.  This makes it easy to check the identity information and ensure that it matches the site that you expected to see.

Use an updated browser
Regularly updated Web browsers like Internet Explorer 7 incorporate an ever-expanding set of features, such as the Microsoft Phishing Filter, designed to help protect you when you click links in e-mail messages.

Is it too good to be true?
If a deal or offer in an e-mail message looks too good to be true, it probably is. Exercise common your common sense when you read and respond to e-mail messages.

To upgrade to Internet Explorer 7 now, visit www.microsoft.com/ie.