I installed COMODO FIREWALL PRO, do I need to leave the Win Xp fireball running or should I disable it? Will they clash with each other at all or is running 2 just a system resource waste.....

i kept windaz firewall running as i had to keep closing comodo to do torrents etc.

id say you can have two firewalls running...........its not as dodgy as 2 avs
BUT
i closed comodo and tried installing pc tools firewall yesterday and it ballsed up the installation, had to uninstall both and install pc tools for it to function correctly

Id personally only have the one firewall running, and to be honest, you may as well not have one as have the windows one.. Having worked, and still occasionally do work securing networks, I can say getting round the windows firewall doesn't take a lot of effort, if you know what to do..

I have always understood dual firewalls to be a bit of a no no.

No, don't do it! They conflict with one another, just as 2 antivirus suites do.

I installed COMODO FIREWALL PRO, do I need to leave the Win Xp fireball running or should I disable it? Will they clash with each other at all or is running 2 just a system resource waste.....

No switch off the Windows Firewall.
They will clash.

i kept windaz firewall running as i had to keep closing comodo to do torrents etc.

id say you can have two firewalls running...........its not as dodgy as 2 avs
BUT
i closed comodo and tried installing pc tools firewall yesterday and it ballsed up the installation, had to uninstall both and install pc tools for it to function correctly

Methebell, can I ask why you are running, uninstalling so many Firewalls.
Are you just trying them out or are you unhappy with Comodo?

Online Amour is currently getting rave reviews, some think it's better than Comodo.
Here's quite an informative article on both Online Amor and Comodo:

http://blog.scotsnewsletter.com/2008/03/24/the-best-firewall-software-of-2008-online-armor/

I'll be tempted to install Online Armor on both my mother's and my sister's PC as it's supposed to be a lot more user friendly for the novice than Comodo but it gives equally good protection.

I have 2 Firewalls and im glad i do!!

Sometimes stuff slips by the hardware firewall. (In my cable modem)

I have 2 Firewalls and im glad i do!!

Sometimes stuff slips by the hardware firewall. (In my cable modem)

One hardware firewall and one software firewall is recommended, but 2 software firewalls are not.

Ah i see :)

Seeing as firewalls plug themselves into the networking stack, technically you can have as many as you like. But i dont really see any benefit if one is doing the job already.

What is a software firewall doing if you are behind a router using NAT with it's own firewall? I think I know but would be interested what others have to say.

What is a software firewall doing if you are behind a router using NAT with it's own firewall? I think I know but would be interested what others have to say.

Inspecting incoming and outgoing packets as it normally would, it's just if you're behind a NAT device and aren't forwarding any ports there won't be any incoming connections from outside of the network i.e. Internet. It will still stop outgoing connections which NAT has no effect on (well, apart from breaking some protocols).