the blu-ray drives going out seems to be the PS3's biggest problem, note: your drive may still play other disc types (CD/DVD), but if one fails to recognize or only does "sometimes" you either A: have to clean it, or B: replace the laser/assembly.
As for your movies showing up in the xmb and playing, gran turismo 5 and sonic did that for me too, then when it got in to the game it would hang (that was the laser not reading it anymore) and then the screen just hangs black, which might be what's happening in your case, check to see if it will load it in your XMB everytime, then listen when it goes black and see if the disc is still spinning. It all really depends, lasers can go bad in any section of it, it may only read and not play, it might completely go out, or only the CD portion may, etc.
Sometimes if you disable the BR's ability to connect to the web (buried in the options), this can help. I had the same issue with LOTR on BluRay, and disabling BR internet connection, it works.
Sometimes if you disable the BR's ability to connect to the web (buried in the options), this can help. I had the same issue with LOTR on BluRay, and disabling BR internet connection, it works.
Good luck.
