Anti-Virus is needed if your runs any Windows operating system. Both Windows XP or Windows 7 require an anti-virus program to protect your computer from email viruses, malicious malware, worms or spy ware.
There are various anti-virus programs available for your windows operating system that are free or open source that will protect your computer from the many threats that can compromise your computer and personal information security.
The most popular open source anti-virus must be Clam Win.
Clam Win runs on any Windows operating systems and will protect your computer from any virus out on the internet. This anti-virus is available for free download from clamwin.com. Read more about the ClamWin open source anti-virus.