WOT is a free program that will warn you before entering a dubious site.
WOT is a further layer of security, but not a replacement for anti virus.
Maybe you are not sure which program will suit your PC? Or you have only tried one all the time?
Remember that not two machines are identical; what works well on one may not be optimal on another.
Try more than one before you decide - but not all at the same time as they may conflict.
- AVG Antivirus: http://free.avg.com/gb-en/homepage
- Avast Antivirus: http://www.avast.com/free-antivirus-download The world's most popular antivirus software
- Avira AntiVir Antivirus: http://www.avira.com/en/avira-free-antivirus
- Spybot Search & Destroy Antispyware: http://www.safer-networking.org/en/mirrors/index.html
- Malwarebytes Anti-malware Antimalware: http://www.malwarebytes.org/mbam-download.php
- Kingsoft PC Doctor 3.3 Antimalware: http://softdl.pcdoctor.kingsoft.com/version/setup_multilang_full.exe
- If you want a 'second opinion' on online scanners try this: http://www.mywot.com/wiki/Online_tools
Free vs. Paid
Please note that "Free of charge" usually means non-commercial & home use only
(and both of these conditions should be met). A paid version is still better, if you can afford it...