volvie–
I haven’t used Norton for a few years. About 3 – 4 years ago many reviewers complained that it bogged down their machines, but over the last couple of years reviewers say that it’s been streamlined and pretty much fixed. Personally, I’ve had issues with the installations of ZoneAlarm and Norton, while McAfee had its recent well-publicized issue of mistaking a key Windows component for a virus and deleting it. Bottom line – there’s no perfect antivirus, but all that we’ve mentioned are good.
One additional advantage I forgot to mention that a commercial program may have is that they may have updates for the latest high-profile virus more quickly, due to their number of employees and their interest in retaining their customers.
kapusta–
If your system is already infected it gets tricky.
You may be able to run antivirus programs, but they might not work properly.
Sometimes booting into safe mode can help.
Sometimes you can boot from another device and run antivirus from there.
Worst case scenario, sometimes the infected drive can be connected to an uninfected computer as a second hard drive and disinfected from there. Be VERY careful if using this method that you don’t infect the clean computer.
Please see my reply to “dov717”, below.
None of the programs discussed here should disrupt or noticeably slow your internet connection, although you may want to tweak some AVG settings if you find it overly intrusive.
dov717–
Malwarebytes is something I used once, on a computer infected with the fake antivirus program “Antivirus XP 2010”.
“Antivirus XP 2010” is a sneaky program that disguises itself as an antivirus program, pops up all kinds of dire warnings, such as “your information is being stolen right now!”, steals the windows security center’s colors and logo, and won’t let many programs, including legit antivirus, run. It claims that it will “fix” the “viruses” it found if you send them money, but all that happens is that they take your money.
I had to download two files on a clean computer; the first was a registry-altering file (just to allow the malwarebytes program to run) and the second was malwarebytes. The files were then burned to a CD, and brought to the infected PC. After malwarebytes ran for about an hour, all the while “Antivirus XP 2010” kicking up its fake warnings, I was prompted to restart the computer. It was completely disinfected, which was very nice to see.