http://www.edbott.com/protect_your_pc.htm
Ed Bott is a byname in the PC world; in this article he outlines the elements of a comprehensive security policy for Windows 2000 and Windows XP machines. Another section on his site:
http://www.edbott.com/windows_tips.htm
Offers a whole host [practically a plethora, though certainly not a surfeit] of articles covering Internet Explorer, Windows Tweaks, Outlook Express, Hardware
Troubleshooting / Maintenance, Privacy / Security, and Windows Update.