Can only connect 1 device at a time. Please help

So here my deal. I have 2 LW drives. They connect no problem. I can however only have 1 device hooked up. So  drive A I have the modem connecting and drive B I have my computer. I try to hook up my TV to Drive A and nothing. If I unplug my computer from drive B the TV now works. If I re hooked up the comp to drive A nothing. I have had a RMA sent to me and still nothing. I must be doing something wrong here.

Hi there, one LW needs to go to a router (not a modem) fot them to work. Can you please be a bit more specific?