Smart Security Firewall

I have used NOD32 for years and it is great. Decided to try the Smart Security for its integrated firewall etc, (trial version), and it seemed fine. I had set it to notify me of incoming and outgoing attempts, and this appeared fine, (and was). Next day when I booted up, nothing connects to internet. I had to disable firewall. I have checked settings till I got lost. Can someone please tell me why it allowed things one day and blocked EVERYTHING next? Edited. Using XP SP3, Nothing else installed. Using 'Unwired' as IP - (but seems to always be the same address). I just thought it odd that one day it was asking me for the rules - allow, not, etc, and it internally has set these rules, but the next day blocked everything and didn't ask. (rules still exist I noted but wouldn't allow anything) Wasn't until I disabled firewall that internet / email worked.