Firstly, get good anti virus software. There is some antivirus software available out there. It is up to you to choose any of this software to protect your computer. However, you may do a research to find out the most powerful anti virus nowadays. Antivirus scanning software, or a virus scanner, is a program which examines all files in specified locations, the contents of memory, the operating system, the registry, unexpected program behavior, and anywhere else relevant with the intention of identifying and removing any malware.
Secondly, install a quality Firewall. There are many firewalls available, some good and some bad. My recommendation is the FREE Zone Alarm. They provide a paid version with extra tools (of course), but I think the free firewall-only option is fine. A firewall is a dedicated appliance, or software running on another computer, which inspects network traffic passing through it, and denies or permits passage based on a set of rules.A firewall’s basic task is to regulate some of the flow of traffic between computer networks of different trust levels. Typical examples are the Internet which is a zone with no trust and an internal network which is a zone of higher trust. A zone with an intermediate trust level, situated between the Internet and a trusted internal network, is often referred to as a “perimeter network” or Demilitarized zone
Thirdly, install an anti-spyware application. There are many available, some good, some bad. Spyware is computer software that is installed surreptitiously on a personal computer to intercept or take partial control over the user’s interaction with the computer, without the user’s informed consent.While the term spyware suggests software that secretly monitors the user’s behavior, the functions of spyware extend well beyond simple monitoring. Spyware programs can collect various types of personal information, such as Internet surfing habit, sites that have been visited, but can also interfere with user control of the computer in other ways, such as installing additional software, redirecting Web browser activity, accessing websites blindly that will cause more harmful viruses, or diverting advertising revenue to a third party. Spyware can even change computer settings, resulting in slow connection speeds, different home pages, and loss of Internet or other programs. In an attempt to increase the understanding of spyware, a more formal classification of its included software types is captured under the term privacy-invasive software.
Fourthly, beware of any suspicious email attachment. Do not open email attachments you are not expecting. Viruses come with some very nasty messages to trick you into opening the attachment e.g. “Your email account has been canceled, see attachment for details”. Even worse, the virus looks like it comes from an email address you recognize e.g. from admin@yourDomain.com (where ‘your domain’ is the domain name that you use). Virus attachments can have the following ‘file extension’: .exe, .pif. If you receive a .zip attachment and open it – make sure it doesn’t contain a file with one of those extensions. Do not open attachments you haven’t requested, even if they appear to be from people you know.