Is Your PC Zombie Free?

Losing control of your own computer

Thousands of individual PCs working together in a network can achieve powerful results and distributed computing, as it is called, is the next big thing.

Already you can use your computer to help find a cure for Alzheimers, model climate change or search radio telescope signals for extra-terrestrial intelligence.

But the search for intelligent life on Earth is going badly. Hackers are using similar techniques to send spam, attack websites and companies and host bogus websites.

If your computer has been infected with a virus or compromised over the internet or you have inadvertently installed spyware it could be dawn of the dead. Your computer could join a network of zombie PCs and the chances are you wouldn't even know it.

Symantec, a maker of security software, estimates that on average 30,000 are turned into zombies each day. Networks of zombies, remotely controlled by spammers, are used to send out up to 80% of the unwanted email that flies around the net. Hackers even sell control of compromised systems for thousands of dollars.

This isn't surprising to security experts who know that an unpatched computer connected to the internet can be compromised in as little as 20 minutes. Symptoms can include unresponsive internet connections, slow computers, and excessive hard drive activity (indicated by the disk light on most machines).

Luckily, you don't need to mess with voodoo dolls to avoid the risks. You know that bit in films where the zombies are staggering down the street and the teenagers lock themselves into a house and try to block the door with bits of furniture? Well, the following three steps are the computer equivalent:

•	Get your software up to date. This can prevent outsiders hacking into your computer and compromising it
•	Make sure you have antivirus software installed. This will stop viruses from infecting your system via email, the internet or downloaded programs.
•	Ensure you have a firewall running on your computer. This sits between you and the internet and stops hacker programs sneaking into your computer and trying to take over. A good firewall can also help if you are infected because it can prevent Trojans and zombie programs from reaching out from your PC.

If you install Microsoft Windows XP Service Pack 2, the built-in security centre will tell you whether you are up-to-date and everything is properly installed. Otherwise, you can check online.