u may find some good info at these sites
go to
http://www.download.com/

get some tools like
if somebody hooking up to your pc
get visual route 2005 (free 15 day trial too)
see who and where
do a search for route or ip tracers
get a firewall
if you aint got one
read up here to learn some tricks ect.


http://www.beginnerspc.com/membersites.cfm#1


http://www.winguides.com/registry/