What is the best antivirus program for free or trial version?

i think avast is great.

What is the best antivirus program for free or trial version?avast

AVG and it's free.

What is the best antivirus program for free or trial version?ducati

I strongly recommend AVG from grisoft, but you can go to download.com search for antivirus in the scroll boxes select your OS and in license select free when the search ends click on editors choice they will appear a few softwares that are recommended from the cnet staff. Also try tucows.com. Also you should get a few spywares i hev installed spybot search and destroy and add-awre 2007 both free both great.