I have several computers running winxp installed in my office, they are all connecting to the WAN providing by the building (wall socket) (DHCP, mask 255.255.252.0). I setup a shared folder in my computer so all other computer in the same group could access it. This configuration have been using for long time. Recently, I am trying to setup a router. I have the WAN port of the router go to the wall socket, connect the NIC to the LAN port of the router, setup the router in DHCP mode (192.168.0.100/255.255.255.0 to 192.168.0.110 /255.255.255.0), I turn off all the firewall (windows one and router's builtin one), the NIC has ip set as DHCP. If I ipconfig/all, I see that the NIC was assigned ip 192.168.0.100. I can access the internal, email whatever. However, the shared folder can no longer be accessed by other computers in the same group. I think it is the problem of ip. But what's really weird is if I turn off the DHCP function in the router, ipconfig/all always give 0.0.0.0/255.255.255.255 and I cannot access the internet. I have no idea what's going on. Anyone know how to fix it and allow the shared folder in application of router? Thanks.