1. How did you connect to each machine when on DSL (i.e., browsing via My Computer, going directly to the machine's name or IP Address)?
2. Did you have to change any specific settings on either machine when setting up the Cable Modem, beyond the addition of the Router (i.e., Machine Name, IP - which should be DHCP)?
3. If you get one of the other machine's IP Address (at a command prompt, type in "ipconfig /all", without the quotes), can you connect to it via the other machine by doing the following:
a. Start --> Run
b. \\ipaddress from other machine (i.e. \\192.168.0.1)
c. click OK, or press Enter
Here's a start, let me know if you've got any other questions or if this didn't make sense. You can also contact me offline at mail_nospam@danwright.us (remove the _nospam obviously).
Dan