Rather than re-type this, please see my post here:
http://www.yorkietalk.com/forums/off...ml#post3376707
Also, if you have a wireless network, be sure to use a good security protocol, and a good network key. It is relatively easy to track computers activity across an insecure network. Example here:
Firefox Extension Allows Anyone to Steal Logins over Insecure Wireless Networks - Softpedia