Before you download files, help protect your computer

Downloading files can include installing programs from a CD, opening pictures or links to Web sites from e-mail, copying Word documents and Excel spreadsheets from the company network, upgrading software acquired from the Web, or transferring music files from a computer half a world away.
Files you download could be just what you expect, but they might also be a vehicle for malevolent intent. Malicious software (also called malware) is software that can harm you or your computer; it can include viruses, worms, spyware, and other unwanted programs.
Before you download files, make sure you are as protected from unwanted software as you can be.
Keep your software safety net up-to-date

Update Windows automatically. If you use Windows Vista, Windows XP, Windows 2000 Service Pack (SP3) or later, or Windows Millenium Edition (Me), Automatic Updates delivers updates to your computer automatically, so that's the easiest and most reliable way to make sure that you get new security and other high-priority updates as soon as they become available. To turn on Automatic Updates, visit Microsoft Update.
If you use Windows 2000 SP2 or earlier, Windows 98, Windows 95, or Windows NT Workstation 4 you can go to Windows Update for the latest security updates. (Make sure to return regularly.)

Regularly download the latest antispyware and antivirus updates, and then scan your computer right away. To do this, subscribe to the program's update service. You can set most of these programs to actively-even automatically-monitor for and help stop spyware and virus intrusions. If you use Windows Live OneCare or Windows Defender for Windows Vista and Windows XP SP2, you can get updates automatically through Microsoft Update.
Improve your computer's overall security

Lay the protective groundwork. Use a firewall, keep your operating system updated with the latest security updates, and use both antivirus and antispyware programs. Learn more about how to better protect your computer.

Set your antivirus program to scan all incoming files and e-mail attachments before you open them. This is different for every antivirus program, so consult the manual or online Help for instructions. If you use Windows Live OneCare you can sign up for Automatic Updates through Microsoft Update.

Use a spam filter. Many e-mail programs offer filters that can help block unwanted messages. Microsoft Outlook has strong natural defenses against junk e-mail, but you can also step up your defense against spam.

Install and run a program to help detect and remove spyware. Some Internet Service Providers (ISPs) include antispyware software as part of their service. If your ISP doesn't offer this, consider Windows Defender. Windows Defender comes with Windows Vista. If you use Windows XP SP2, you can download Windows Defender for no charge.