WOT is a free program that will warn you before entering a dubious site.
WOT is a further layer of security, but not an antivirus replacement.
Maybe you are not sure which suits your PC? Or you have only tried one all the time?
Remember that no two machines are identical; what works well on one may not be optimal on another.
Try more before you decide - 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 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
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...