help needed HOW TO PREVENT from INTERCEPTED NETWORK

I have some problem with the network connection
is there any software or solution to prevent from
intercepted network ?
same time my pc network get intercepted by some body else
that what i try to solve
maybe fool statement
but it did happen
and is there some kind tracker sofware
that can use to tracking
where is the intercepted located at the same time
when intercepted person doing it or
just any thing simple to prevent it or secure my network?

maybe some anti key logger software or any tracking software
or any anti intercepted network sofware
please any information that related with this topic
thank you

Yes, please clear that up a bit. Do you think someone is getting into your network, or intercepting your traffic? Get a good firewall to protect your network (there are free software based firewalls available.)