Firewalls

After receiving incredible, mind-saving advice from this site on how to rid my computer of adware/spyware, I thought I'd pose a question to those who know much more about computers than I. Background: I run my own small company (very small-two computers) and have a desktop that's wired into a wireless router with a cable modem. I have a laptop that I use that connects to the office network. Whenever I try to add the extra protection of a firewall (on either computer), I lose the ability to communicate on my network, whether it's file sharing, printer sharing or otherwise. I'd like to use a firewall for additional protection but it doesn't seem possible with my current configuration. I was told by the computer setup person when he hooked up my network that my wireless modem (D-Link DI-524) has a firewall built in and hence I don't need the individual computers to have one. However, I am unsure as to the truth of that statement. Any help is greatly appreciated.

Most times they come with a basic firewall, but like I said, very basic. It depends on how your network is setup. I would keep trying… What I reccomend is with your firewalls, make sure that they will not block the ip of the other computer. Good luck, wng