Hiii all

Recently, my computer was hacked into and i lost certain very valuable data...Ever since then i have got paranoid about making my computer secure...i have installed zone labs freeware firewall and updated my computer and removed almost all malware...however, a few days back i visited a security website and that website informed me that my ip address and certain personal info was not hidden...i am very distressed...cud someone plz advice me as to how to hide my ip address on the net...
thanx
swatii