AVG Anti-Virus Free Edition
AVG Anti-Virus Free Edition was PCWorld's top pick in April 2012's Free Antivirus You Can Trust. It performed well in virtually all of the tests we ran.
In our real-world malware detection tests, which evaluate how well an antivirus package will block brand-new threats, AVG's freebie blocked 85.7 percent of the samples, tying for the best result among the programs we tested. It detected 98.7 percent of the more than 129,000 samples of malware from the past four months in our malware "zoo" test. That's a good score, although a bit short of the best results we've seen.
AVG was at the top of its class in disabling active malware infections: On our test PC, it detected and disabled all malicious software, and removed all traces of malware two-thirds of the time.
AVG also scans a PC relatively quickly. When we directed it to check 4.5GB of data, it sped through the job in 1 minute, 35 seconds, the third-fastest time in this test and only 4 seconds slower than the fastest. Its on-access scanner--which runs when you open or save a file--took 4 minutes, 55 seconds to go through the same amount of data, about average for the programs we looked at.
I like AVG's main interface, though its advanced settings could intimidate some users. Apart from that caveat, if you're looking for solid, fast PC protection, look no further than AVG.