The first part of this problem problem comes from the fact that each router creates its own private Class C subnet, with its own range of IP addresses. For example one router could be set to an IP address range of 192.168.1.1- 254, with the second router set to 192.168.2.1- 254.

This doesn't present a problem for Internet connection, but it complicates File and Printer sharing because Windows' network browsing features (Network Neighborhood / My Network Places) don't work across subnets.

The second issue is that the NetBIOS broadcasts that Windows' network browsing uses are blocked from entering a router's WAN (Internet) port. Even if you open up the appropriate ports (TCP and UDP 137 - 139) in your router's firewall, the first issue will still prevent automatic network browsing from working.

However, you still can file and printer share among computers connected to each router, but you'll either need to know the IP address of the computer you want to connect to and enter it into either Windows' Find Computer utility, or open Start > Run and type ipaddress where ipaddress is the IP address of the computer you want to connect to, i.e. 192.168.2.2. Another method involves the use of LMHOSTS files on each computer, but we won't go into that method here.