How to tell if your PC is secure


A recent US survey revealed that more than 80% of computers are infected by a form of malicious software (also known as 'malware'). However, only 6% of those infected were aware that their computer wasn't secure.

Malware can infect your PC when you:

  • Install or download a program which appears harmless.
  • Visit a web site that contains malicious code, or which permits unscrupulous advertising practices.
Generally, you should be wary if your PC is running more slowly than usual, or has developed a tendency to crash for no reason. However, there are other warning signs that your security may have been compromised.

Here's a quick guide to how you can detect malware, and what to do about it if you have been infected.

Adware

Adware can increase the number of pop-up advertisements you see when browsing web sites. If you notice an increase in the number of pop-up ads on web sites you visit, it's worth scanning your system for adware. Anti-adware offers a free scanning tool.

Persistent cookies

Most web sites you visit leave cookies on your computer, and on the whole these are perfectly harmless. But spyware cookies track your surfing across different web sites and build a picture of your behaviour for marketing purposes.

Spyware Watch offers a list of spyware removal programs and links to the businesses selling them (or giving them away).

Trojans

Trojans open your computer to hackers, allowing them to control it remotely in order to monitor your online activities, infect other people on your network, or send out spam.
Trojans usually infect your computer through a virus, perhaps as a result of you opening an infected email.

Homepage hijacking is a favourite trick of Trojans - if the homepage you usually see when you log on to the Internet changes inexplicably, this is a sign that you could have been infected.

Worms

Worms are particularly dangerous, since it's very difficult to spot them once they've infected your system. They can reproduce and spread equally silently to other computers, they can send emails without your knowledge, and they can be used to steal your passwords on secure sites.

Installing a firewall can reduce the risks from Trojans and worms (although you may not eliminate them if they're already on your computer).

Update your PC with anti-virus software updates and patches released to address specific problems. If you use Windows, check the Microsoft site for new patches, and consult your Internet Service Provider (ISP) or anti-virus software provider for advice on the latest threats.