Had a neighbors Toshiba laptop that was REALLY screwed up. It had a current version of Norton and still allowing malware to pop-up. Tried AVG, same result. Tried Avast, same result. Put in Kaspersky and it found the malware and four other instances of adware and removed them.
Kaspersky, when it comes to security, is tops.
I know few people who would disagree.
AVG is good too, just not able to handle a severe pre-infection. AVGAS, however could have handled that instance pretty well. The two together are quite effective.
I will also vouch for Nod32 which is almost as good as KAV, and my favorite, F-Protect- It is quite effective in detection, and is very cheap if one has multiple computers: $35/5machines/yr, or the corporate $45/10machines/yr
I pay for KAV, NOD32, F-Protect, and BitDefender on an annual basis, as they form the nexus of my detection software on my test benches, along with AVG AntiSpyware and Trojan Hunter.
Regardless of what the AV testing sites may say, these have been the most effective for me over the years, Even though I annually test all of the available AVs and ATs, except for Norton, which has earned my ire...