I have Norton Anti-virus installed. Is it necessary to have CounterSpy also?

Norton is a system hog, but it does the job, sort of. Depending on whether you have Norton system security or the Norton Internet security suite, or just the anti-virus is going to determine if you need any additional programs. Running 2 anti-virus programs on 1 machine is not a good idea as they will conflict with each other, however, running 2 or 3 anti-spyware anti-adware programs is a good idea as some will catch certain items that others may not....also running some sort of software firewall and spyblocker program is also effective. Personally I would not use Norton for anything, but since you already have it and paid for it, use it. AVG has a free anti-virus program and a Pro version that integrates into the shell of your system and has a firewall built-in....it only takes up resources when running active scans but still monitors everything on the PC....now no program is totally inclusive and isn't going to catch everything but the more pro-active you are in your security the better; Norton tends to be more of a reactive program in that it doesn't really protect until after there's something there.

I have Norton Anti-virus installed. Is it necessary to have CounterSpy also?antivirus software

i recommend using only one antivirus because you may have problems if 2 are running.

I have Norton Anti-virus installed. Is it necessary to have CounterSpy also?computer virus