Have a sumsung bdc 5900 player thats worked fine for 4 months but now when i put a blu ray disc it wont play but will dvds or cds

There is a problem in the laser pickup assembly, blu ray discs require a higher velocity and more precision to play than standard dvd's, if you still have warranty return the unit because there is nothing more can be done.

Have you tried to connect you player to the internet and update the device? If that doesnt work call samsung for a repair http://www.samsung.com/us/support/contact