Here are a few links for keeping your systems secure from Viruses, Spam, Spyware, and also a link for Internet Safety.
For Anti Virus software that is free to download for the home user, called AVG, go to http://www.grisoft.com/us/us_index.php.
The next link is for a Firewall for your home computer, again free to
download off the Internet: go to here and click on the link for Shields Up.
Adaware is a free programm that scans your computer and removes all sorts of unwanted stuff - if you have not used it you may be surprised what is lurking there!
You can also use Spybot Search & Destroy on your system that does what Adaware does but without the deep scanning.
The following link is for Internet safety. The World's Oldest and Largest Internet Safety Organisation is at http://www.cyberangels.com/.