Up until about a year ago, the only protection I used on my computer was the Spybot/AdAware combo. I used these programs for almost 6 years without any problems and still use them once in a while, still, today. But things have changed. One day, I got a very bad virus on my computer. I went to use Spybot and to my surprise "Access was denied". AdAware worked but it found nothing. I started doing research, I downloaded AVG. I installed it, ran a scan and found the virus. I removed the virus..... Later the same day, out of paranoia, I ran another scan. The same virus was found again!! And not only that, the virus had installed a bunch of its little friends as well. I removed them with AVG.... Ran another scan... Removed them again!! They just would not go away..... I attempted to do some more research but, Internet explorer would not work. Access was denied! I went to run AVG again..... Access was denied to it as well.... Even in safe mode I could do nothing! It was horrible!! This virus rendered my computer useless... I went to a friends house and did more research. I found many different answers, many different ways to combat this... I ended up downloading about 20 different programs, (Combo-Fix, Dr.Webb, Hijack this, etc etc). Somehow, I hacked my way into the permissions and restored my privileges to use AVG again. Again I removed the viruses... I followed up with Spybot... and removed some more... I ran Iobit Antivirus and removed some more... Eventually, using many different antiviruses there was no more viruses!!! I was so happy and very proud of myself, it had been 5 days. The next day, to my horror, the viruses had created themselves again and now it seemed it was using AVG against me, Iobit showed that it had been infected, somehow altered, and yet again I was locked out of most everything. At this point the only thing I could do was to go back into safe mode and copy onto a flash drive as much of my files as I could fit before inevitably, after many days of stress, and lack of sleep, I finally broke down and reformatted my computer losing almost everything I had...
After I got windows all setup again I vowed that I would never let this happen again. I researched for weeks on this subject and found what works best for me.
This is my current setup:
1. Comodo Internet Security Suite Free (Firewall installed Only).
I found that the Comodo Firewall was one of the best Firewalls on the market and had been very reliable in ratings with many websites for the past few years. The rest of the Comodo Internet Security Suite although above average is not to par with many other Antivirus programs, but like I said the Firewall alone is Top Notch and allows you to decide if you want to let something in or not. This is usually done with guidance of course. A firewall such as this is a very important key in keeping your computer virus free. Used effectively it is all you need, but I wouldnt advise it.
2. Avast Antivirus Free
This in my opinion and many others is the best Antivirus program you can get free or not. Avira Antivirus though better at detecting viruses than Avast and AVG, scans your computer slower, is very unreliable at updating virus definitions, and is a bit heavier on system resources. But if I had to choose between Avira and AVG it would definitely be Avira for the Best protection and much lighter resource needs than AVG not to mention what AVG allowed a virus to do to itself... But I pick Avast over both of them!! Avast is very fast, very light on resources, updates itself automatically many times a day, and also on top of having the best (in my opinion) Virus detection next to Avira features real time protection for your computer and the internet, stopping almost anything that gets through Comodo firewall, (or that you allow through), dead, before it has any chance to hurt your computer.
3. I also keep a copy of Malwarebytes Anti-Malware handy just in case a trojan somehow slips through, because, (after the fact of course), I learned the virus I had was the dreaded Conficker Trojan and Malwarebytes is known to be able to destroy it.
Like I said, this is the best setup I have. There any many like it but this one is mine :). And I do strongly recommend it, but of course as you know there are many different opinions out there, and different setups work better for different people. So, be very picky!!!
Sorry for the long post, thank you for reading it and most of all, I hope it helps...
Heres a couple links for research (all free of viruses
Firewall ratings: http://www.matousec.com/projects/proactive-security-challenge/results.php
AntiVirus Performance Tests PDF: http://www.av-comparatives.org/images/stories/test/performance/performance08a.pdf
An Antivirus Poll with common results: http://www.freewaremission.com/2009/08/best-free-antivirus-poll-report/