The number of computer viruses and their intelligence increases day by day. Malicious programmers around the world keep on finding new ways to circumvent even the best antivirus firewall software. Whenever a virus has been neutralized by the security software companies a new loophole is found and a new virus is born and ready to beat your security program. You must therefor never neglect PC security - always have a decent program running on your PC.
It is impossible to keep a PC clean from malware without proper antivirus firewall software. Installing security software does not present any challenges and after that it takes care of all future updates all by itself.
It is not uncommen that people ignore the scheduling of periodic system scans or sometimes setting them at a time where the computer will usually be turned off. In order for the antivirus firewall software to offer the best possible protection, you must allow for regular scans of your PC. Eventually a computer virus will get through but then it will be caught at a later time. This has happened to me once. Scanning your PC every once or twice a week is therefor very important - the more you surf/download from the internet, the more important this gets.
The best antivirus firewall software in my opinion is a program that has it all: antivirus, anti spyware, anti adware, popup blockers, etc. Then you wont need to get more than one program. Lots of different programs are available and you may already have heard of some of them.
Selecting antivirus firewall software presents several challenges. I recommend focusing on how many known threats is the program capable of detecting and how often are new updates released. You could of cause listen to other peoples opinions and maybe check out a couple of forums, that discuss such matters.
Lastly you also have the option of trying a free scan with most programs.