remolal, The last firmware you loaded was most likely for a player that has a Hold\Lock function and it is activated.
Try turning on the player at the main switch while holding down the play button, if that does not work repeat the operation again trying all the other buttons on your player.
If that still does not help download the Product Tool Here:
http://www.mympxplayer.org/product-t...ads-df234.html
Use it to try and install another firmware, you will notice there is a format button if it becomes active press it to format your player, then try to load the firmware.