According to this
First please describe your setup exactly. It should be something like this
1. Cable or DSL modem connected to CATV cable or phone line.
2. WAN port on router connected to modem with straight thru cable.
3. PC connected to one port on router. TiVo USB to ethernet adapter (if your TiVo doesn't have an ethernet jack) connected to another router port - both with straight cables.
4. Ethernet adapter connected to TiVo USB Port. PLEASE GIVE US YOUR TiVo model and ethernet adapter model.
Assuming this is true your PC should be able to configure your router by using your browser to connect to http://192.168.1.1
For now turn all encryption on the router off (wireless router only) and set your router to obtain IP automatically. Reset the modem first by unplugging it, waiting 30 sec and plugging it back in.Wait a few minutes then do the same with your router.