Free Firewall for small business

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Dose anyone know of a Free Firewall for small business I use zone alarm free at home but in the EULA it says not for commercial uses.

I'm starting up a auto repair shop and want my files to be safe on my computer and not get sued for not paying for a program not for commercial use. I also Backup everyday my files/books to one of my flashdrives.

Its not a top of the line computer its a old 1.8ghz p4 with 1gb of ram (Dell Dimension 2500) with XP home install with CD Key that was on the case.

Currently Using Windows Firewall but last night a friend of mine (a kid) got infected with just that, mostly due to poor browsing practices.

Just Looking for something to protect my computer so I can continue being productive.

Found Comodo Firewall Says its free for Commercial and Private Use, Though I have never used it before i have seen it recommended on here.

 

Look into: http://www.opendns.com/