If your computer is connected to the net your computer is at risk from attacks by cyber criminals. What do you do to avoid them. These hackers use the flaws inthe OS to gain access to your system and convert it into a Zombie. In effect what happens is that, you pay for the computing chip which processes other's works. Other things which you can do are to install a router, it acts as another line of defence in the internet.
Be sure you use the Anti-Virus, Firewall,Anti-Spyware software. Is best to use the professionals. Read technical blogs for latest updates on security breaches, and take care of your computer. If you are using Wi-Fi then make sure you use encrypted standards otherwise people may evasdrop and hack your system from proximity.
This list is not an exhaustive list of preventive methods, only indicative.