check your security on your router to make sure it is able to be recognized on the Xbox 360. the connection settings should walk you through the whole process ( if I remember right) ( I have not set up the wifi on my Xbox 360 in about 3 years now I think)... look up the manual of your Xbox and see if there is anything on the wireless setup.

I would take a can of air and carefully blow out the port screen... If you can, use a flashlight and see into the screen and check and see if there is any rips or tears in the speaker... If it is blown you will need a new one and also to prevent this turn your volume down two notches for the ringer and notifications aswell as media... I have been doing that for years and still have crystal clear audio out of my old motorola razar