Don't mention the war (and die)

One of the more vexing questions for us computer users is how to keep our systems safe from all the nasties out there. (And don't snigger, Mac owners - the news is not all good for you, either.) If you have any sort of connection to the internet, you are prey to viruses, malware, phishing attacks and goodness-knows-what. It's like war out there, except it's in here. The scary thing is that, while it is relatively simple to put some reasonable protections in place (stressing the words "relatively" and "reasonable"), a lot of people don't bother to do the basics.
One of those basics is keeping your operating system up-to-date to fend off the baddies that try to creep in through the back door. The fixes are called "patches", and if you have a PC, Microsoft issues new patches every month to fix new security issues that have come to light. You can set up your computer to accept these patches automatically (if you're not sure how, email me). Sadly, many users ignore patching their systems (and if you are on a dial-up connection, I can understand the hassle of downloading big files all the time). According to PC World, though, the message simply is not sinking in.
Most Mac owners smugly think they are immune from the attacks that have bedevilled PC users for years. Another PC World article shows that is no longer true. Be warned!
If I haven't already made you paranoid, according to PC World, 2008 was a record year for the increase in malware.
Apart from system patches, unless you are behind a company firewall, at the very least you should have installed on your computer a firewall, an anti-virus program, and tools to keep you clean. The following are some I use (and all are free):
WinPatrol: protects your computer from Adware, Spyware, Worms, Trojans Horses, and alerts you to intruders trying to change your system.
Threatfire: protects your PC against attacks by detecting malicious behavior, such as capturing your keystrokes or stealing your data.
Ashampoo Firewall: This company makes seriously good software, and their free firewall is as good as most commercial products.
CCleaner: (The first "c" stands for "crap!). A freeware system optimization, privacy and cleaning tool.
Spyware Doctor: Detects, blocks and removes all kinds of spyware.
Adaware: Another good defence against spyware.