|Avast, Avira, and AVG are all good free ones that I have used in the past. |
Lately, however, I really like Panda Cloud Antivirus. It is free for home use, and makes use of the power of cloud computing to allow it to scan files in real time without putting a strain on system resources. On top of all of that, it is pretty much ready to go right out of the box. It can be downloaded at http://www.cloudantivirus.com. The only downside is that the machine has to be connected to the network in order for the scanning to work properly, which is not a big deal for most users.
Please let me know if you have any other questions.
IT Desktop & Network Consultant - MOS Master Certified, MCP Certified, CCNA Certificate Pending, A+ Certified.