Alternative browser:
http://www.mozilla.org/products/firefox: -- A new and free web browser from the original creators of Nestcape now called the Mozilla Org. I strongly recomend PC users to switch to using FireFox to browse the internet to avoid several security vulnerabilities (like the ones mentioned below) found in Internet Explorer. It has a pop up window blocker and tabbed browsing among other features.

Spyware removal:
http://www.lavasoft.de/support/download/: -- for removing "spyware"(a type of virus), download Ad-Aware from their site. If you are runnign Microsoft Windows and Internet Explorer, at some point you will be tricked into installing some "spyware" that will record the sites you visit and slow down your machine.

http://spybot.safer-networking.de/index.php?page=download: -- also for removing "spyware" download Spybot-S&D from their site.

General security resources:
http://www.microsoft.com/security Microsoft's main security home page. This is a great resource for reading about vulnerabilities and fixes.