You might try resetting the player by turning on the unit, make sure the tray is empty and press-and-hold the STOP button on the player.
If that doesn't help, it problem may be a hardware issue, and would require service.
Bought 3 months ago and have played 2 BD's on it when I first got it. I haven't installed any updates and now it will only play dvd's. Loading a BD it just says loading... then the tray opens. I've tried 4 different BD's that play fine on my PS3. I have a warranty but I'm looking for something I'm possibly doing wrong. I have hdmi out to a vizio 47" lcd and spdif in from a pc(which shouldn't make a difference). It has no internet connection as I use Win7 Media Center for all of my tv/hulu/pandora/netflix/mymovies.