try disabling the media server connection on your ps3 and disable the media sharing from your pc that the modem is directly connected to. i had the same problem but mine was a belkin n1 vision router. i did everything but it didnt work, i also asked lyndon for help, he gave me some useful advise and i learned a lot from him, thanx lyn. but the major problem for me was that my router needed a firmware update. i updated it then it didnt work at all.after that my laptops also didnt work aswell. i went online for help and it sed i hav to first take all the cables off my modem, then get a cocktail stick (or sumat sharp) and hold the reset button for 20 secs, take the power cable off the router (dont let go of the reset button) and wait for 20 secs, then put the power cable in (dont let go of the reset button) and wait for 20 secs. then it will go into download mode. do the same process agen and it will start working. WELL IT DID FOR ME and now it only goes off ONCE every 2 or 3 weeks. hope it helps. i know how it feels when you cant play online.
Best of Luck!!!!!!!!!!!!!