black bars in BSPlayer

I use mostly BSPlayer to watch anime and everything else. I use Zoom Player and some other things once in a while, but mostly BSPlayer. Yesterday, black bars suddenly started appearing on the top and bottom of some files, like they would if you were watching a widescreen movie on TV. How can I get rid of these bars? They weren't ever there before, and I don't like them. I've looked around is BSPlayer's preferences and did a Google search for help, but I just couldn't seem to fix it.

Any help would be appreciated, thanks!

Is it possible that you were watching video files with an aspect ratio other than 4:3 on fullscreen with them stretched to fill the whole screen? If that's the case, the black bars are supposed to be there, though if you must insist on distorting the video so it fills the screen there's probably a "maintain aspect ratio" option that's been switched on somewhere.