Did you change the default password on the router and setup it up for the best security
The default passwords for most routers can be found on the web in 30 seconds.
here is some info for router security;
http://www.google.com/search?q=setup...ient=firefox-a
I would at least turn on windows firewall.
If you go to questionable sites then you should get a good software firewall.
here is a good review;
http://www.matousec.com/projects/fir...ge/results.php
I use comodo v.2.4 as it is less annoying than v.3 :0