I have a working MS Windows network at home, and want to add a computer runnng kubuntu. I've installed samba (although I don't know how to check if the installation is ok), set the workgroup name to be the same as my existing Windows network and set my ~/Public directory to shared and I have shared folders on the Windows, but the Windows computers can't see the Linux computer and the Linux computer can't see any samba shares (should it be able to see itself?), giving me a message "Unable to find any workgroups in your local network. This might be caused by an enabled firewall". I've tried Googling that message, but I don't understand anything I find. What do I do next?

I'm a networking and linux newbie. Please be gentle!