The best defense against viruses is legitimate antivirus software with updates AND KNOWING THE EXACT NAME OF YOUR ANTIVIRUS PROTECTION!
So many users when asked: What do you use for antivirus? - do not know exact name of the program. Often the answer is “I have something, but don’t remember the name”, in best case they know part of the name.
That’s exactly what creators of malware rely on: Using names very similar to legitimate products.
So, if you are out there browsing Web Pages and all of a sudden a message pops up saying something like:
Your computer maybe at risk – click here to run a scan or install this to protect your computer – You should be able to read that message and say to yourself: “I know my antivirus program, and this is not my antivirus giving me this message. This is probably something pretending to be my antivirus program tricking me into downloading it.”
See examples of some internet scams by clicking subpages link at the bottom of this page.
Free antivirus for macs:
http://www.apple.com/downloads/macosx/networking_security/iantivirus.html
Free antivirus for pcs:
http://free.avg.com/ (click DOWLOAD AVG FREE link)
They also have more advanced version for purchase.
Not free, but very effective for pcs:
Spyware, Viruses and other malware cleaning tools:
http://www.bleepingcomputer.com/combofix/how-to-use-combofix
From Kaspersky
http://www.kaspersky.com/support/viruses