Denise,
After having made those changes (and having saved them) you need to, in ordet ... the order is important:
Power off the modem
Power off the router
Restart the modem and wait for it to boot completely
Restart the router and wait for it to boot completely
Open a command prompt and do a flush DNS.
The order is important because all of those devices will cache DNS values and use them even though changes have been made.