I've got a us robotics 9112 I can access the user interface via the usb use the net but when I connect the ethernet cable I can't access the user interface at 192.168.0.1 so I can't browse the web either!

When you are connected with USB make sure that the DHCP service is running on the router, as it sounds like it isn't.
Basically this means you are not getting a valid IP address and so no connection.

Don't really know much about dhcp yeah even the help thing says no valid ip address and it said go to cmd and check the subnet mask and all... when I connect the ethernet cable I get a 100% data loss... the thing I'm confused why is the net working while connected via the usb and not the ethernet cable... u mind telling me how to check and turn on the dhcp service on the router?

You need to read the manual as it is covered there in great detail.

I did but nothing is there I did everything check the subnet mask reconfigure the ip everything nothing works