There is a huge variety of software available for securing a PC from unwanted attention be it malware, spyware, hacking or online surveillance. Companies like Norton provide excellent products but at a cost.
For many people in need of such protection including many in China, Burma, Vietnam, Thailand and other countries in the region these pr0grams are too expensive.
But there are effective ways of keeping your PC safe with freeware or at minimal cost.
Eric Geir writing on the eSecurity Planet website has some great tips and websites to go to if you want security without a huge outlay.