Something wont register

ok so i connect by verizon fios on a windows comp & it works fine.
mac connects wirelessly by airport & when i first set it up, it said it was connected [full bars] but the internet did not work. a day later, it said it was connected & worked fine.

now the internet got disconnected, when it turned back on, same issue, windows computer works fine, but mac says its connected & is not.
ive tryed turning everything off & done everything that i know how to [not alot] & its not working, & now its been a day.

mac has full bars & says that its connected but the internet WONT work. how do i bascilly get it to register that the modem is there & get the 2 things to work together to get the internet?????????

Sounds like a security issue. Using a Verizon supplied Actiontec router? (FIOS doesn't use a modem) If so, access the internal menu and turn off all security as a test. Make sure the airport settings are correct in your machine. You should be using DHCP and the Verizon DNS settings. Most locations where FIOS is used the DNS settings are generated automatically so you may not have to worry about them.

As a last resort, attach an ethernet cable from the Actiontec to your Mac to see if you can connect that way.

Regards.