Hardware Firewall vs Trojan Horse

[Sam]

I have just reinstalled windows xp on one of my computers, so have not had the time to install a software firewall or antivirus yet. As luck would have it, one of the kids managed to get a trojan horse virus on the computer within a day of the reinstallation. Unaware of this, until I installed an anti virus program, I have been using the infected computer as normal i.e. accessing email, using passwords etc.
What I would like to is can the trojan horse send my personal information (email, passwords) from keylogging back to hackers if I have a hardware firewall, I have no NAT configured.

[justin]

Some hackers use trojans in DoS attacks against other companies/servers.
I recommend looking at your computer activity logs to see if there was an outgoing connection that you didn't know about You should also change ALL of your passwords.

[Mel]

It's one of the worst firewalls/virus scanners out there right now. Use something like Norton (which isn't free, but it's 10x better).