I have been doing some research on Antivirus products as of late, with the poliferation of malware that is attacking Windows based system it is a necessity to have, suprisingly there are numerous AV vendors offering free solutions for at least one year.



CA-Antivirus http://www.my-etrust.com/microsoft/



AVG (Free) http://free.grisoft.com/freeweb.php



Mcafee (Class action lawsuite settlement for previous users, version 3-4)



http://software.mcafee.com/lcas/



AntiVir Personal Edition



http://www.free-av.com/



Free Online Scanners...mcafee, norton, panda, and a host of others offer this free service...but they are not replacements for a full blown Antivirus product.