I download a free anti virus program called "Avira" free. http://www.free-av.com/ It was rated the best free anti virus software by consumers report. I tried it and was satisfied with the protection it gave especially for a free program So I decided to buy the premium edition about $20.00 bucks. The program is very excellent, it will catch malware, spyware, adware, trojans, virus programs, etc, before they try to install themselves onto your system. And deny access or delete the intruder. You get a window that gives you choices on what to do. Avira free or premium edition does not use up a lot of resources, AVG is good but it uses a lot of system resources. The ones I don't like because of resource usage is Norton, McAfee, Trend Micro, and the worst of all is Panda. Do not install these programs as they well eventually take over your windows based operating system and you will need to go into the registry to clean them out. Sometimes just an uninstall option will not work, so a thorough registry removal is necessary, and this will take 1 to 2 hours to do. Believe me I have done this for many of my clients. You have to know what your are doing, other wise you can delete certain registry commands that could render your operating system useless, such as in the case of removing Norton from your system via the registry. Norton uses a windows system 32 file that actually write itself into the boot up process of windows OS. "Avira" updates itself every time I log on to my computer but only if your internet connection is automatic. Otherwise you will need to do an update manually, after you connect to the internet. All in all it is a very good program. Another program rated number 1 for purchase by consumer reports was "Eset" a very good program that I installed on a friends laptop and it is very dependable.