You might perform a reset on your unit by holding down the FF "button" on the unit for 12 seconds. It will reset itself, and should allow you to set up the unit to your new router.
I'm unable to reset my wireless router connection on my BD-4600. I need to switch wireless routers, but the setup>internet connection>wireless menu doesn't allow me to change my settings. When I select the current router, it attempts to initialize - there is no way to select a different available router. The other router is in range (checked with my laptop). As is, I can't connect to my Netflix...