Audio Systems: Car stereo problems, honda civic, fm radio

Question
I recently installed my car stereo in my 2000 Honda Civic DX. I bought the car used and the person who had it before me had XM radio and I think he left the XM "antenna" on the roof and I believe it's still connected somewhere and the regular AM/FM radio wont work. Sometimes I get static and one station 107.1 but most of the time I get nothing. My CD player works fine. What do you think I need to do exactly.

Answer
xm antenna in the roof or insie the car makes no diference
buy a 410 antenna from the auto parts put in top of the dash and plug that in to the radio, if this don't work you have a bad radio
and most likely that will be the problem

and you have to go return the antenna ,