Something about your home network doesn't make sense.
If you have the cable from your modem plugged into your router, does plugging your MacBook with another ethernet cable to the router give you an internet connection?
OMG !!! greaaaat news.. you see after u told me to hook the cable straight to the PS3 & i tried it & nothing happened.. Well , after that i changed back the setting to wireless & did the test & it's ON .. ))
well thanx a lot 4 ur help.. i would still like to understand what happened or the cause... thanx again man..