Before you spend a dime on security, there are many precautions you can take that will protect you against the most common threats.
1. Check Windows Update and Office Update regularly Click on the Automatic Updates tab in the System control panel and choose the appropriate options.
2. Install a personal firewall. There are a number of free versions available online.
3. Install a free spyware blocker.
4. Block pop-up spam messages in by disabling the Windows Messenger service (this is unrelated to the instant messaging program). Open Control Panel | Administrative Tools | Services and you'll see Messenger. Right-click and go to Properties. Set Start-up Type to Disabled and press the Stop button. Bye-bye, spam pop-ups! Any good firewall will also stop them.
5. Use strong passwords and change them periodically. Passwords should have at least seven characters; use letters and numbers and have at least one symbol. A decent example would be f8izKro@l. This will make it much harder for anyone to gain access to your accounts.
6. If you're using Outlook or Outlook Express, use the current version or one with the Outlook Security Update installed. The update and current versions patch numerous vulnerabilities.
7. Buy antivirus software and keep it up to date. There are free options also available online.
8. If you have a wireless network, turn on the security features: Use MAC filtering, turn off SSID broadcast, and even use WEP with the biggest key you can get.
9. Join a respectable e-mail security list, so that you learn about emerging threats quickly and can take proper precautions.
10. Be skeptical of things on the Internet. Don't assume that e-mail "From:" a particular person is actually from that person until you have further reason to believe it's that person. Don't assume that an attachment is what it says it is. Don't give out your password to anyone, even if that person claims to be from "support."
- source PC Mag