A firewall is designed to permit or deny network transmissions based upon a set of rules.
Antivirus or anti-virus software is used to prevent, detect, and remove Viruses and Malware find out more.
Antivirus software is designed to regularly scan your computer and find viruses and other malicious software that might be on your computer. It is up to you how often you run it, though generally it is recommended that you run it nightly or at least weekly. If the software finds a virus, it typically destroys it. In addition, most anti-virus programs will protect you while you do everyday activities such as check e-mail and surf the Web.
If you download a file onto your computer from the Web or from e-mail, the scanner will check and verify that the file is virus-free. The software will also update its "antivirus definitions." These definitions are updated frequently as new viruses are found, this is because new viruses are being released all the time.
Recomended Free Antivirus Software:
Microsoft Security Essentials
Avast Free Edition
Power management is a feature on computers and computer peripherals such as 
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite (TCP/IP) to serve billions of users worldwide. <more>
PC tips and tricks and techniques for maintaining, building, upgrading and networking your home PC.