Tassibo, if you are running windows xp it does come with a firewall, its crappy but better than nothing. maybe turn that off and try, then download a solid firewall.

Go to Control Panal

Then Network and Internet Connections

Then Network Connections and click LAN (if that is what you have.)

Then under the General tab select properties

Then select the advanced tab and uncheck the internet firewall tab.

I am sure you know where it was but someone else may not.

Good Luck, I hope you get limewire up!