Contrary to many other antivirus programs, avast! Pro Antivirus is a lightweight program that will protect the computer without slowing it down to a crawl. You can even run the program on very old computers.
avast! Pro Antivirus is available in a free version for non-commercial use. However, the free version is lacking some important features, like protection against the dangerous rootkits. Read more about the free version on the page Technical Info.
You will probably do fine with the standard settings of avast! Pro Antivirus, which means you can install and forget the program. Then you will not notice the program until it finds a virus or another threat to your computer. However, if you want to, you can easily change the settings of the program and its components to your needs.
avast! Pro Antivirus will of course protect you from viruses, but the program will protect you from many other dangers as well. You will be protected against spyware that want to spy on you and your behaviour in order to send the information to the maker of the spyware. This is mostly a privacy issue. You will be protected against the much more serious threat from rootkits that will hide itself deep in your windows in order to steal your log in codes to your online bank or other sites where they can steal your valuables, or from where they can make it possible for a hacker to remote control your computer.
You will also be protected against malicious scripts on websites and against malicious attachments in e-mails.
You can tell avast! Pro Antivirus to send warnings to an e-mail address. That way you can see if a computer is being attacked even if you are not physically near the computer. This is very convenient if you install the program on a server in the basement or on the computer of a child.
If you install avast! Pro Antivirus on a child's computer, you can protect the program with an access code. That way they cannot alter the settings or turn off the program.
Usually virus makers have an advantage compared to the makers of antivirus programs. In the arms race the virus comes first, then the antivirus makers has to discover the virus, make a definition file, and then distribute the definition file to their users. Thanks to a heuristics filter, avast! Pro Antivirus can identify a virus, even if it is not in the programs definition file, thus it is able to stop an unknown virus!
avast! Sandbox makes it possible to run potentially exploitable programs like your browser in a safe virtual environment. That way an exploit of the program cannot harm the rest of your system. avast! Pro Antivirus also includes a code emulator that can test the behavior of a suspicious program without actually running it. Thus checking if the program is malicious or not.
Gaming Mode automatically detects if you are running a full screen application like a game. If so avast! Pro Antivirus will suppress pop ups and notifications, so you will not be disturbed while playing. avast! Pro Antivirus will still protect you; it is only the messages that will be disabled.