The first thing you do is back up your data.  Always do this first.  If you don't backup first and the detection removal process scrubs or corrupts files then you'll lose them forever.

Next, you head over to the Norton or Kaspersky community forums.  Either search for or start a thread with your question.  If you really need to check for malware it's more complicated than just getting a "good" security suite.  There can be multiple tools to use and boot sequence steps to follow.  If you don't follow the analysis steps you can miss something or it can mask itself.

Once you're past that stage then you can setup a security suite.  I like F-Secure, Microsoft Defender / Security Essentials, Norton, and Kaspersky pretty much in that order.  I'm using Microsoft Defender on the Win8 boxes, Kaspersky on a Win7 portable desktop, and MS Security Essentials on the XP box.  Every once in a 6 months or so I run MalwareBytes Anti-Malware for a complete file scan.

The biggest difference seems to be that paid versions have more bells and whistles.  Norton and Kaspersky will aggressively scrub tracking cookies if you set them that way.  The free versions don't.  Norton's full suite will setup registry cleaning, disk defrag analysis, and report high cpu/mem/disk usage if you configure it to do so.

Originally posted by Torvaldr

The first thing you do is back up your data.  Always do this first.  If you don't backup first and the detection removal process scrubs or corrupts files then you'll lose them forever.

Next, you head over to the Norton or Kaspersky community forums.  Either search for or start a thread with your question.  If you really need to check for malware it's more complicated than just getting a "good" security suite.  There can be multiple tools to use and boot sequence steps to follow.  If you don't follow the analysis steps you can miss something or it can mask itself.

Once you're past that stage then you can setup a security suite.  I like F-Secure, Microsoft Defender / Security Essentials, Norton, and Kaspersky pretty much in that order.  I'm using Microsoft Defender on the Win8 boxes, Kaspersky on a Win7 portable desktop, and MS Security Essentials on the XP box.  Every once in a 6 months or so I run MalwareBytes Anti-Malware for a complete file scan.

The biggest difference seems to be that paid versions have more bells and whistles.  Norton and Kaspersky will aggressively scrub tracking cookies if you set them that way.  The free versions don't.  Norton's full suite will setup registry cleaning, disk defrag analysis, and report high cpu/mem/disk usage if you configure it to do so.

I consider Norton to be AAA Malware. If I see a PC that has it installed I always recommend to remove that asap. 

F-secure has never let me down. It has caught files on other people PCs when connected via LAN when their own didn't catch them.

kaspersky for 2 years though the best one i ever had and prob will get next year was Webroot. But its up to you...i usually go off of what this site says:

http://anti-virus-software-review.toptenreviews.com/

The best layer of security is simply knowledge.

But besides that, I use Microsoft Security Essentials since it seemed the lightest from what I've seen. I haven't had a virus in probably 10 years, which is when I really didnt know what I was doing with a computer.

Avast, +1.

Light on your computer, yet very safe. Years using it and I have not had any virus/worm/whatever attack once.

On top of that, it's free.

I have Kaspersky. I heard its slow and stuff, and once it got its databases corrupted and I decided its a good moment to try another one. I tell you, Kaspersky is the hands down best antivirus there is.

I tried a LOT of free or trial antiviruses. Avast, Panda, many others. I never had SO MANY problems.

What is bad about other anti-viruses:

1) Some of them miss obvious viruses. Like, I had a clearly infected file (i KNEW it was infected) and they wouldnt recognise it as a virus. I never had a virus ever pass Kaspersky's defenses ever in my whole lifetime experience with it.

2) Some of them have problems with false positives. Insane problems. Its like, it finds thousands of viruses on my pc and when i read on the viruses it found, its something like "generic malware", meaning, its not a virus really, just antivirus decided the file MAY BE bad and goes raging about it.

3) What's even worse, some of them have no option to ignore a file. Everything antivirus deems to be a virus is REMVOED ON SIGHT. No trial, no chance to be forgiven.  Needless to say, those also usually have a high rate of false positives.I lost 3 hours of my life fixing what that one did!

4) Some of them have very complex or nonexistant restoration procedure. Either you cannot restore files antivirus removed as they were detected as viruses, or process is very clunky, counter-intuitive and so on (one antivirus had me to manually choose a folder where to place a file for restoration because it "couldnt place it into source folder automatically", this was HELL)

Bottom line, what is bad about other antivirus software? They either:

* have a big enough failure rate to be noticeable, meaning false positives or false negatives, and with antivirus software this IS important.

* do not give you, user, enough freedom about how you want to deal with detected files, instead saying "this is better for you, so you have no control what i will do to your files, they' all are  belong to me"

* have clunky or nonexistant file restoration procedures

* have clunky or nonexistant option to add exceptions

Kaspersky has no such problems. Detection is very good. When it detects malware, it tells you exactly what it detected, and allows you to choose what to do with it - ignore, add exception, quarantine, heal, delete. When it detects suspicious activity, it doesnt say "virus generic malware" it tells you exactly what is going on - what registry program tries to modify, what global keyboard hooks its trying to register, what other process memory its trying to access. When you tell it to shut down, it shuts down w/o questions. When you tell it to ignore a file forever, it does so without questions. You can restore files from quarantine at your own choice and it isnt very complex process.

I'm sticking with Kaspersky from now on.

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Originally posted by asmkm22
Microsoft Security Essentials.  Low profile, unobtrusive, and catches just about everything the other stuff does.  A lot of the other free stuff end up bugging you about buying their upgraded versions and whatnot, which gets annoying.

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Same here. I used Avast happily until some time ago they pushed through an update for x64 but incorrectly used x32 that had me out of commission for a couple of days. I'll be damned if I ever use them again.

Antivirus's are garbage. All they do is eat memory. If you're getting viruses you either need  to upgrade your ancient OS or quit clicking on/downloading stupid crap.