why can't my modem see my router, I can hook router directly in to the modem and it doesn't see it.

[olegrannie]

My modem went out, I got a new modem and now I have no wifi, because the modem can not see it, so I again replaced modem and bought new router..same thing. I need wifi because of health problems and I am elderly, please help me. Thank you

 

[Reynod]

Please provide us with more information about the modem / router.

Model number, brand etc.