The best fully free antivirus software

Tweet

If you use a fully free antivirus software, what is it? Would you recommend it to other mylot users? Don't forget to post a link so people who are stuck with no antivirus or one of the bloody expensive ones have something to check out. I use Avira AntiVir (www.avira.com), which I find really good. The Personal Edition is totally free and it is pretty good at keeping your computer safe. There's even a Guard mode that spots viruses whenever they appear on your hard drive, then warns you. The drawback? Every time it upgrades (about once per day) there's an ad. One. That advertises the Premium Edition. Which costs money. But I don't care. It's great and free.