[newbie] Hacker on Licq

[Robin Regennitter]

Yesterday, some hacker from Spain got into my system and started to hacking
away at some of my linux files especially in Licq files.  Also  I know that
some of my files in the /usr/share directory has also been manipulated.
There were features that were useless.  How do I prevent this from happening
again?  Is there a good firewall program I can use?

Rob