ESET smart security for my computer

My computer is acting crazy again and i dont know why. I keep getting some weird error messages whenever i want to run new installed programs. Once i click the debug button, the whole system crashes. Sometimes, it will restart on its own too. My friend told me it may be due to some malicious virus that my anti-virus cannot detect. I've already updated my anti-virus to the latest version and the same thing still persists. I think it's time i ask the technician to come by my place and once he's done fixing whatever's causing the problems, i'll ask him to install this ESET smart security that my friend recommended. he says it's by far the best computer security software that he's used. Time i give it a try myself and see how good it is.