There is no such thing as total panacea to all problems. I used Bitdefender years ago on a couple of XP systems and it ran fairly well, that was then. Since the advent of Win7 I've been using the Kaspersky Internet Security package on 4 systems and it has performed nearly flawlessly. There so many different trains of thought when it comes to A/V security software that discussions could go on and on. A couple of free tools that are good to have in conjunction with A/V software(s) would be Malwarebytes and Superantispyware, they are available free and are reasonably effective for Malware and/or spyware. There are other freebies as well but I'd suggest researching on the net before I got too carried away. The Kaspersky Security suite is NOT cheap but I have yet to have a major infestation issue since I started using it.
I purchased Bitdefender AV on 2012 and as I was to learn later one, it was the most ineffective, unreliable Anti-Virus program one could ever purchase. Last Jan 2012 my PC was infected with an FBI virus despite having their AV software and because I am ignorant of what to do under that circumstance, I took my PC to a shop and had the virus removed after paying $119.54. 4 weeks later the same thing happened and this time because I could not go online as the virus locked me out completely I once again had to take to the same shop to remove the virus. In between, I contacted their CS and their response almost suggested I was at fault for not knowing what to do in that event. To spend more than $400. to take care of a problem their program was supposed to prevent and when it didn't, their excuse was that the virus mutate and in essence, there's not much they could do about it and that I should have contacted them before I did anything. Given this obtuse explanation I decided it would be best to drop them and subsequently asked for a refund but was told that since I purchased it from a 3rd party, they can't do anything. Being completely ignorant of this (all I know is that I bought it from their website) I swallowed my anger and took it up as a learning experience. Given this experience, I would not recommend Bitdefender to anyone. In my experience their product is simply unreliable and their customer service is just as bad if not worse. In my opinion any one promoting their product would be guilty as a co-conspirator. PS: I have copies of my email to their CS supporting what I just stated.