Actions you can take
There are a number of steps you should take to keep your computer safe.
You need to do this to look after your own interests - just the same as you lock your car and keep your cash card PIN secret.
Be informed
Make sure you have a basic understanding of what your computer does, and what sort of things can go wrong. There are plenty of resources your can research, such as CERT and NetSafe.
Be careful
Take care, especially with email attachments, and particularly if they are an executable type (even if it comes from someone you know).
Be cynical
Don't believe everything you get told on the internet. Check out claims with some independent source, eg use google.
Use a firewall
Make sure you have a firewall to protect your computer. Windows XP has one, if you installed the SP2 update. Or, you can use a built in netpacket filter (as in Linux) or a separate hardware firewall (like an ADSL router) or install a software firewall (like ZoneAlarm).
Update
Keep an eye out for updates (aka patches) that fix security holes in the software that you have installed.
If you use Microsoft Windows
- Get a virus scanner (such as AVG) and make sure that the virus scanner's definition file is regularly updated
- Get a spyware scanner (such as Adaware and MS Spyware)
- Disable hidden filename extensions
- Check the internet security settings
Using Microsoft products like Internet Explorer and Outlook Express can be an extra risk. This is because
(a) they are more popular and so more viruses are written for them, and
(b) this software has more defects.
You can avoid a lot of virus and security problems by avoiding Microsoft products. For example, use Firefox for web browsing or Thunderbird for email (both run on Windows). With a little more effort, you can avoid Microsoft altogether by using another operating system like Mac, Linux, BSD, etc.