Anti-Virus and Firewalls
A good Anti-virus program is essential in today's Web World. You don't always have to pay lots of cash for a good Anti-Virus Program. Here is one that is endorsed by CNet, the premier on-line technology site. AVG. There is a Pay version and a free version which is available to Non-Commercial User. Give it a try. Go to http://free.avg.com/ and find the Free Version to download.
A good Firewall is also essential to prevent threats from the outside cyber world. One of the better ones is Zone Alarm. http://www.zonealarm.com . It will prevent threats from getting to your computer. Go to the web site to find out more.