Step four to securing your system:

Keep SPYWARE and MALWARE off your PC

What is spyware?   Trend Micro Demo

"spyware is being redefined as a much larger category of rogue software called "malware", or malicious software programs.  At its most basic definition, spyware/malware is when insidious little software programs covertly install themselves on your computer, and then perform secret operations without your permission.  Once in place, malware programs may do hundreds of nasty things to your computer.  They will log your keystrokes, steal your passwords, observe your browsing choices, spawn pop-up windows, send you targeted email, redirect your web browser to phishing pages, report your personal information to distant servers, and serve up pornography.  This malware will operate invisibly, often without displaying itself in your Task Manager.  To top it off, malware usually refuses to be uninstalled through your control panel, and requires special tools to delete them from your drive.  Yes, this is a direct cousin to viruses, but with a broader portfolio of wicked intentions."
From: Spyware 101: Understanding The Biggest Internet Threat of 2005

Peer-to-peer file-sharing networks like LimeWire, Kazaa, Morpheus, Grokster, can be dangerous! Beware; if you're using these networks, you should know that “You also open up your system to a host of security and privacy threats, including viruses, worms, Trojan horses, snooping, data theft, spyware, and not to mention slow performance of speed.” For a more detailed article on file sharing networks see File Sharers, Beware

a.  To remove spyware use these popular, affective and freely available spyware removal tools:

Adaware SE
Spybot Search and Destroy - Enable automatic Windows Updates

Microsoft Guide - Security at Home: (Spyware) Protect your PC