Disable the file sharing, don't let people take from you. People are uploading some illegal files to these poor kids computers that leave them on all the time, unprotected. If you use Kazaa, close it, and shut down the icon in the lower right hand corner by the clock as soon as you are done.
Record companies (this is my opinion---no facts to support it) are uploading lots of viruses and other things with Kazaa and other file sharing programs to infect the computers of people who use this system. They can't stop file sharing, but they can cause damage to people who do.
There are other risks beside viruses and trojans.
I have a client who got a letter from one of the local cable service provider, indicating that their "Internet Security Protection Team" had monitored someone uploading "illegal" images to their home computer. The client was horrified, and the kids had no clue, but with an open window to the internet via Kazaa, lots of things can and do flow in unknown to you.
I was a bit horrified to know that the cable companies are "observing" the images flowing through their system, but this is a new era of scrutiny of information which is deemed "dangerous" and/or illegal by authorities.
(In case you don't know what "illegal" images are, it is child pornography....and if those images are on your computer, you could go to jail.)
The internet has the very best and worst of all avenues of life streaming into your home once you go on line.
Just like our bodies are full of things we don't even know about, germs, parasites, etc. from the foods we eat----our computers can be filled with many things we don't even know about, so be careful out there, OK?
If you don't take the necessary steps to protect yourself and your computer, you may be in for a rude awakening some day.