spidds

My 04 TL now displays "please check disc" on the nav screen after I disconnected the battery to install a subwoofer. I thought it was a bad disc but after ordering and inserting the new 3.9 orange disc, the screen still displays the same message. My question is: Could my issue be a bad dvd drive if I'm not able to access the navigation clock, diagnostics tools(guide, menu, cancel) ?????