1. Use anti-virus software and keep it up-to-date -
Anti-virus software protects your computer from viruses, a well-known security risk. With new viruses appearing daily, virus software quickly becomes useless if you don't update it.

2. Use one, or more, anti-spyware programs -
Free tools are available for identifying and removing spyware, adware, and various other non-virus malware. These types of files are often installed by Trojan programs, some freeware and shareware applications programs, or as "drive-by installations" from various websites. These programs invade your privacy and interfere with your work by transmitting your personal information to their creators, opening unwanted pop-up windows, and noticeably slowing your computer's performance.

3. Keep your operating system and other software current -
Keep your operating system up-to-date as well as any programs used to access the Internet. When manufacturers find vulnerabilities that pose security risks, they create and distribute patches for the product. These updates are usually free to download. Many programs can be set to update automatically when connected to the Internet.

4. Do not download files from an unknown source -
Be careful of what you download and what you agree to when you click "yes" to prompts from installation or popup windows. Many programs do more than what they advertise. Many "web browser aids" are actually spyware. Also, be wary of downloaded programs that seem to do good things because they could actually be causing harm or opening up new security holes on your computer. A number of programs are designed to give other people access to your computer without your knowledge.

5. Use complex, hard-to-guess passwords and change them regularly -
Any security measures you take can be undermined by a password that is easy to guess or a computer account that does not have a password. Good passwords help keep your computer secure from external threats (such as hackers) and local threats (such as a nosy roommate or coworker). Try to avoid words that are in the dictionary. Create passwords that are a combination of letters and numbers, and upper and lower case letters.

6. Do not open email or attachments from unknown sources -
Email is one of the easiest ways to transmit computer viruses and Trojan programs, which can give other people access to your computer. If you don't recognize the email sender, don't open the attachment(s) with it. If you get an attachment from someone you know but weren't expecting one, don't open it until you ask the sender about it.

7. Use Peer-To-Peer (P2P) file sharing cautiously -
The installation of peer-to-peer file sharing programs can bring spyware onto your computer and open it up to some viruses. Most file sharing programs also default to opening shared folders for read and write access, allowing distribution of the folder contents. If you must use P2P, stick with software the utilizes the BitTorrrent protocol and only share one subdirectory for P2P communications.

8. Use a firewall to protect your computer from Internet intruders -
Computers connected to the Internet should use a personal firewall to filter out unauthorized or potentially dangerous traffic from the Internet, while allowing good traffic to reach your computer. Firewall hardware and software is available at computer stores and is built in to some operating systems/updates, such as Windows XP Service Pack 2 (SP2). Use firewall software that scans both incoming and outgoing Internet traffic.

9. Back up your computer data regularly -
The failure of a computer hard drive, or the mistaken deletion of a data file, can be devastating. Don't risk the loss of your valuable data, especially your music collection or digital photos.

10. Keep your computer clean on the inside -
Desktop computers can rapidly accumulate dust and pet hair. At least every 6 months, open your computer case and gently blow or vacuum the dust away. Take great care not to touch internal components or rapidly spin internal fans. Cleaning will help to prevent overheating, greatly reducing the risk of hardware failure.