Unfortunately there is no one "best anti-virus program" to protect yourself, but with a combination of these free programs you can feel much safer while doing your thing on the net.
Be sure to update you software regularly:
Avast Antivirus
or AVG Free (but not both) you shouldn't have more than one Antivirus Program on your system.

And these are a must for Adware and Spyware removal:
SpyBot
And
Anti Malware

To ensure all the junk is removed you will want a registry cleaner:
Wise Disk

Posted in Labels: registry cleaner, the best free anti virus