Just displays 'CARD' when turned on.

Just displays CARD and won’t turn on.  Checked the sdcard in other devices.  ~2500 files.  Worked last night, but not this morning.  Any ideas?

Try resetting it?

What happens if the SD card is not inserted in the player when you turn it on?
Make sure your card is formatted as FAT32. 

Maybe try to use a 8gb, 16gb or 32gb card.