• A research by a security firm Webroot shows that Thailand, the US, and the UK have the highest rates of computers infected with secret programs, tracking what people do with their machines.

    Also according to this anti-spyware firm, almost 55% of consumer Windows PCs are infected with so-called adware, a form of spyware.

    The most malicious spyware programs lurk unseen on PCs and steal confidential information such as passwords or login details.

    Spyware and adware often travel alongside file-sharing programs or media files that people download from the web.

    Free anti-spyware programs such as AdAware and Spybot are used by many people to clean up their PCs.